Dozens of Yemenis were killed in overnight gunbattles in the capital, government officials said on Thursday, as fighting aimed at ending President Ali Abdullah Saleh's three-decade-long rule threatened to ignite civil war.
Residents were fleeing Sanaa by the hundreds, hurriedly fastening possessions to the roofs of cars, hoping to escape the violence that has killed more than 40 people since Monday and threatened to spread into other parts of the capital Sanaa.
The defense ministry said in an Internet posting that at least 28 people were killed in an explosion in an arms storage area of Sanaa in Thursday's early hours.
Yemen's state prosecutor ordered the arrest of "rebellious" leaders of the tribal group led by the al-Ahmar family and a government official said the headquarters of an opposition television station had been "destroyed," without giving details.
Tribal leader Sadiq al-Ahmar told Reuters there was no chance for mediation with Saleh and called on regional and global powers to force him out before the Arabian Peninsula country plunges into civil war.
"Ali Abdullah Saleh is a liar, liar, liar," said Ahmar, leader of the Hashed tribal federation. "We are firm. He will leave this country barefoot."
The United States and Saudi Arabia, both targets of foiled attacks by a wing of al-Qaida based in Yemen, have tried to defuse the crisis and stem any spread of anarchy that could give the global militant network more room to operate.
"We call on all sides, on all sides, to immediately cease the violence," U.S. Secretary of State Hillary Clinton told a news conference in Paris on Thursday.
"We continue to support a united and stable Yemen and we continue to support the departure of president Saleh who has consistently agreed that he would be stepping down from power and then consistently reneged on those agreements," she said.
Leaders of the Group of Eight also called on Yemen's president to quit on Thursday.
There are worries that Yemen, already teetering on the brink of financial ruin, could descend into a failed state that would undermine regional security and pose a serious risk to its neighbor Saudi Arabia, the world's biggest oil exporter.
The most recent clashes have been concentrated in a part of northern Sanaa where fighters loyal to Ahmar have been trying to take over government buildings.
Broken glass, bloodstained corridors and a makeshift clinic for the wounded attested to the damage at Ahmar's mansion, while Sanaa residents heard the sounds of explosions ripping through the city in the midnight hours.
"Clashes are ongoing around Sanaa airport, and I think the airport is now closed," Ahmar said. A government official had said the airport was briefly closed due to the fighting but had reopened.
Government officials did not provide details on from which sides the dead and wounded came from the overnight fighting. Each side blamed the other for the violence, which the opposition said could spiral into a civil war.
In Sanaa, there were long queues at bakeries, banks and petrol stations as residents tried to stock up on cash and food before fleeing to safer areas in the impoverished state.
U.S. diplomats leaveThe United States ordered all non-essential diplomats and embassy family members to leave the country. "The security threat level in Yemen is extremely high due to terrorist activities and civil unrest," the State Department said.
Qatar also temporarily suspended the operations of its embassy in Yemen, withdrawing its diplomatic staff, broadcaster Al Jazeera said.
The most recent round of fighting erupted a day after Saleh, who has ruled the country for nearly 33 years, pulled out for the third time from a deal mediated by Gulf Arab neighbors for him to step down and make way for a national unity government.
Pressure has been mounting since February, when protesters inspired by democratic revolutions in Tunisia and Egypt began camping in squares and marching in their hundreds of thousands to call for Saleh to go. His attempts to stop the protests by force have resulted in hundreds of deaths.
U.S. President Barack Obama has called for Saleh to sign the deal but analysts said Washington has little leverage in Yemen even though it has sent about $300 million in aid to help prop up Saleh's government.
"What options do we have to force a resolution? Almost zero," said Barbara Bodine, a former U.S. ambassador to Yemen.
City at war Saleh said on Wednesday he would make no more concessions to those seeking his departure. But the capital of the country of 23 million has begun to feel like a city at war.
Fighters in civilian clothes roamed some districts on Wednesday and machinegun fire rang out sporadically.
Electricity was intermittent and many city center streets were deserted in the afternoon, but for government checkpoints.
The area around the Ahmar compound resembled a ghost town after the dust settled from the latest firefight.
Long lines of cars snaked out of the city, bags piled high on their roofs, even as gunmen blocked entrances to prevent tribesmen from bringing in reinforcements, witnesses said.
Witnesses and officials said supporters of Ahmar, head of the Hashed tribal federation to which Saleh's Sanhan tribe also belongs, controlled several ministry buildings near Ahmar's compound including the trade and tourism ministries, as well as the offices of the state news agency Saba.
Saleh told a group of invited reporters including a Reuters correspondent on Wednesday that his government was "steadfast."
"We are bearing the shocks of what happened from the sons of al-Ahmar: the chaos and the attacks on state institutions, the press and the Ministry of Industry and the Ministry of Interior. This is a provocative act to drag us into a civil war"
But General Ali al-Mohsen, a regional army commander who has sided with protesters, called on the armed forces to defy the president. "Beware of following this madman who is thirsty for more bloodshed," he said.