Bahrain's streets were mostly empty after bloody clampdown, but thousands defied authorities by marching in cities in Libya and Yemen as the wave of political unrest continued in the wake of uprisings that toppled leaders in Egypt and Tunisia.
The willingness to resort to violence against largely peaceful demonstrators was a sign of how deeply the monarchy fears the repercussions of a prolonged wave of protests.
U.S. officials taken by surprise at the crackdown urged government leaders to show restraint in the country that is home to the U.S. Navy's Fifth Fleet and a strategic ally on oil supply lines from the Gulf.
As anti-government protests rock the Middle East, the White House, Secretary of State Hillary Clinton and the Pentagon all urged Bahrain's leaders to pull back after police attacked demonstrators in the Gulf kingdom's worst violence in decades.
Clinton said she expressed her "deep concern" in a telephone call with Bahrain's Foreign Minister Sheikh Khaled bin Ahmed al-Khalifa and emphasized that violence should not occur on Friday, when many in Bahrain may attend funerals of those killed or prayer services.
People had been gathering in Pearl Square since Monday in an attempt to emulate the successful protest camp on Cairo's Tahrir Square, but police cracked down in predawn hours Thursday.
New York Times columnist Nicholas Kristof, who is in Bahrain, said that more than 600 people had been treated for their injuries and an opposition lawmaker, Ibrahim Mattar, told Reuters that 60 people were missing.
"Bahrain is a friend and an ally and has been for many years," Clinton told reporters. "We call on restraint from the government, (and) to keep its commitment to hold accountable those who have utilized excessive force."
Clinton, who has called on Arab leaders to heed the complaints of their citizens, said Bahrain's leaders should do the same and implement promised democratic reforms.
"We urge a return to a process that will result in real, meaningful changes for the people there," she said.
U.S. Defense Secretary Robert Gates spoke by phone Thursday morning with Crown Prince Salman of Bahrain, according to Pentagon officials quoted by NBC News. "He discussed the current security situation with the Deputy Supreme Commander of the Bahraini Defense Force," they said, without further elaboration.
Pentagon and U.S. military officials told NBC News they were "surprised" by the violent Bahraini police crackdown.
"We're concerned over the crackdown," and "watching events very closely" one senior official said.
Military personnel at 5th Fleet headquarters in Bahrain are not on a "heightened" state of alert, although they have all been instructed to exercise caution and prudence when off base, officials told NBC News.
Ban Ki-Moon, secretary-general of the United Nations, said the reports from Bahrain overnight were "deeply troubling" and also urged nonviolence.
Police firing teargas and buckshot moved in at around 3 a.m. local time Thursday (7 p.m. Wednesday ET), dispersing some 2,000 people, including women and children. "They are killing us!" one man said after the operation began.
"This is real terrorism," said Abdul Jalil Khalil, of Bahrain's main Shiite opposition party Wefaq. "Whoever took the decision to attack the protest was aiming to kill." Mattar said that Wefaq's lawmakers had decided to resign from parliament in protest.
Government: Get off the streets
Bahrain's leaders banned public gatherings and sent tanks into the streets Thursday, intensifying a crackdown that killed five anti-government protesters, wounded more than 200 and turned a hospital into a cauldron of anguish and rage against the monarchy. Along with two who died in clashes with police Monday, the new killings brought the death toll this week in Bahrain to seven.
Barbed wire was in place on streets leading to the square Thursday morning, where police cleaned up flattened protest tents and trampled banners.
The Interior Ministry declared the protest camp "illegal" and warned Bahrainis to stay off the streets.
"The security forces have stressed that they will take every strict measure and deterrent necessary to preserve security and general order," an Interior Ministry spokesman said on Bahraini television Thursday afternoon local time.
Police action was necessary to pull Bahrain back from the "brink of a sectarian abyss," the Gulf Arab state's Foreign Minister Sheikh Khaled bin Ahmed al-Khalifa said on Thursday. " It was a very important step that had to happen, police took every care possible," Sheikh Khaled said at a news conference also attended by the United Arab Emirates' foreign minister and the secretary general of the Gulf Cooperation Council, a loose economic and political bloc of Gulf Arab states.
Gulf Arab foreign ministers meeting in the Bahrain capital on Thursday evening planned to discuss the unrest in the Gulf island kingdom, state news agencies said earlier on Thursday.
A statement from Bahrain's defense forces, quoted by the Qatar news agency, said about 50 security force members had been wounded by demonstrators using "swords, knives and daggers."
"Security forces had to fire teargas and stun grenades to avoid losses," the statement said, adding the military had deployed in Manama "under orders to take all necessary measure to preserve peace and stability for citizens and residents."
King Hamad bin Isa al-Khalifa offered condolences to relatives of two men killed earlier this week and promised to investigate.
View from U.S.
Gates said the U.S. has been encouraging reforms in the region for some time.
"The truth is I think the U.S. has consistently — primarily privately, but also publicly — encouraged these regimes for years to undertake political and economic reforms because the pressures were building," Gates told the Senate Armed Services Committee. "And now they need to move on with it and there is an urgency to this."
Analysts said the wave of unrest has so concerned leaders in the Gulf that they are willing to risk bloodshed.
"It was one thing when it was happening in Tunisia and Egypt and another when it arrives on their doorstep," said Toby Jones, an expert on Bahrain at Rutgers University. "The (Gulf rulers) are closing ranks now and showing how they are prepared to deal with challenges to their power. Their first instinct is to act quickly. It may be messy, but they don't want this to linger.
U.S. officials say the key issue regarding the Bahrain security situation is how much "tolerance" officials have for continuing demonstrations in heart of Manama, NBC News' Robert Windrem reported.
"It is uncertain," said a U.S. official, "whether such a small country, with such small security forces, can continue to show tolerance for increasingly large demonstrations. This isn't Egypt where the leadership knew it had a reserve of a million men in uniform, whether military or security forces, and knew it could if it had to retake the square."
A U.S. official told NBC News that the Obama administration is not backing away from its strong alliance with Bahrain, but that the United States does plan to hold the monarchy accountable for the "heavy-handed tactics" against protesters.
"There are specific red lines" that cannot be crossed, the official said, adding that the U.S. will not tolerate the violence seen Thursday morning.
The official said that for now the U.S. is going to help Bahrain "through some tough love" and honest dialogue. "We are going to try to help them, but we are going to call a spade a spade," the official said, adding that the violence "surprised" the U.S. administration.
Blood on highwayCNBC television news, citing U.S. military sources, said there was a significant amount of blood on King Faisal Highway, in a different part of the city than Pearl Square.
It reported that authorities were confiscating camera phones from individuals suspected photographing affected areas. Activists circulated Twitter messages telling people to delete images to avoid protesters being identified.
Hours after Pearl Square was cleared, the military announced a ban on gatherings and said on state TV that it had "key parts" of the capital under its control.
Police prevented people from getting close to the square, which features a 300-foot (90-meter) monument with a giant representation of a pearl atop it, a testament to the island's pearl-diving past.
The smashed tents, broken chairs and other debris that was swept up by authorities was seen dumped in the yard of a police station.
Salmaniya hospital was thrown into chaos immediately after the police raid. A steady stream of dozens of wounded from the square were brought in by ambulances and private cars. Nurses rushed in men and women on stretchers, their heads bleeding, arms in casts, faces bruised. At the entrance, women wrapped in black robes embraced each other and wept.
The Health Ministry put the number of wounded at 231.
Many families were separated in the chaos. An Associated Press photographer saw police rounding up lost children and taking them into vehicles.
Outside the medical complex, dozens of protesters chanted: "The regime must go" and burned pictures of the king.
"We are even angrier now. They think they can clamp down on us, but they have made us angrier," Makki Abu Taki, whose son was killed in the assault, shouted in the hospital morgue.
"We will take to the streets in larger numbers and honor our martyrs. The time for Al Khalifa has ended," he said.
Helicopters clattered over the city and tow-trucks dragged away cars abandoned by protesters, their tires squealing on the Tarmac because the brakes were still on.
Elsewhere in Manama, life went on as usual. In one smart area, foreigners sat in cafes or strolled in jogging clothes.
Earlier, Kristof said in a series of Twitter messages that the Bahrain government had ordered ambulances to stop going out. He said 10 ambulance paramedics had been attacked by Bahrain police. "I interviewed them, saw their injuries," he wrote .
"Nurse told me she saw handcuffed prisoner beaten by police, then executed with gun," Kristof added.
An ambulance driver claimed a Saudi Arabian army officer had "held gun to his head" and threatened to kill him if he helped the injured, Kristof said in a Twitter message. that a source close to Bahrain's rulers had denied claims that Saudi Arabian troops were involved, but added they were ready to help if needed.
Kristof said the hospital had seen more than 600 people injured in the protests by early Thursday morning.
Calm before stormingMohammed, a 28-year-old banker who asked his last name not be published out of fear for his safety, told msnbc.com that the mood at Pearl Square on the evening before the police attack was calm, with people barbecuing, distributing water, and sitting with their laptops. No one anticipated clashes with police, he said.
“They said that they did warn the protesters, and that’s not very accurate,” he said. “They were armed with rubber bullets, bean bag rounds, and long sticks. The police unit head requested everybody back off from a very small speaker, from 700 meters away. It was 3 a.m. A lot of the protesters were asleep; they did not give them enough time to respond. It was complete chaos.”
Mohammed said a crowd staged a sit-in at the medical complex where the wounded and dead were taken.
“Between 1994 and 2000, we had huge tension in Bahrain. When a marcher was executed by the regime, the government would not allow a burial procession because that’s when people gather and it turns violent. They used to take the body and bury it themselves. They are fearing the same thing today. People knew they had to be at the hospital, or else they might lose the chance of seeing the body or saying goodbye.”
Bahrain learned a lot from Egypt and Tunisia, he said.
“The protests in Bahrain for the past 40 years were nothing like this. It was just youth here and there. They would get into clashes with the government police, and basically be sent back home. But now it’s peaceful, it’s organized, and they were very, very determined to stay [in Pearl Square] for as long as it takes.”
“International news agencies, when they look at a protest of 3,000 or 4,000 people, they think it’s a small thing. Bahrain has a population of 500,000. We cannot get a million like Egypt can. There are people who have a good life. It’s not a movement for food or for power, even though those are some of the demands. Its’ a movement for the constitution, and to get more of what the country and the economy can give to us.”
Dr. Sadek Akikri, 44, said he was tending to sick protesters at a makeshift medical tent in the square when the police stormed in. He said he was tied up and severely beaten, then thrown on a bus with others."
"They were beating me so hard I could no longer see. There was so much blood running from my head," he said. "I was yelling, 'I'm a doctor. I'm a doctor.' But they didn't stop."
He said the police beating him spoke Urdu, the main language of Pakistan.
A pillar of the protest demands is to end the Sunni regime's practice of giving citizenship to other Sunnis from around the region to try to offset the demographic strength of Shiites. Many of the new Bahrainis are given security posts.
As the crackdown began, demonstrators in the square described police swarming in through a cloud of eye-stinging tear gas.
Many families were separated in the chaos. An Associated Press photographer saw police rounding up lost children and taking them into vehicles.
ABC News said its correspondent, Miguel Marquez, was caught in the crowd and beaten by men with billy clubs, although he was not badly injured.
Race called off
A lower-tier open-wheel race in Bahrain was called off Thursday amid the crushing response by riot police. The cancellation comes less than a month before the season-opening Formula One race at the same track.
The Bahrain Grand Prix is scheduled for March 13, with F1 workers due in the country 10 days earlier.
Organizers said the GP2 Asia Series race set for Friday and Saturday was canceled at the request of the Bahrain Motorsport Federation because of "force majeure" — a French expression referring to uncontrollable events.
The protesters' demands have two main objectives: Force the ruling Sunni monarchy to give up its control over top government posts and all critical decisions, and address deep grievances held by the country's majority Shiites who claim they face systematic discrimination and are effectively blocked from key roles in public service and the military.
Any prolonged crisis opens the door for a potential flashpoint between Iran and its Arab rivals in the Gulf.
Bahrain's ruling dynasty is closely allied to Saudi Arabia and the other Arab regimes in the Gulf.
Shiite hard-liners in Iran have often expressed kinship and support for Bahrain's Shiite majority, which accounts for 70 percent of the island's 500,000 citizens.