JERUSALEM — Israeli warplanes bombed southern Gaza on Thursday following a series of deadly attacks by gunmen in southern Israel that left at least eight people dead and dozens wounded.
The airstrike killed the chief of the Popular Resistance Committees and four other members of the armed Palestinian faction in the southern Gaza Strip, the group said.
The Popular Resistance Committees, which often operates independently from Gaza's Islamist Hamas rulers, identified their dead commander as Kamal al-Nairab. An Israeli military source confirmed the airstrike in the town of Rafah.
The airstrike came hours after squads of men armed with heavy weapons, guns and explosives crossed into southern Israel from Egypt's Sinai Peninsula, attacking a bus and other targets. At least seven Israelis were killed and about 25 people were wounded, the military said.
The Israeli government blamed Gaza militants for the brazen attacks.
The violence stoked concerns about Palestinian militants exploiting instability in Egypt.
"I saw two men in fatigues shooting at me," the bus driver, Benny Bilbaski, told Israel Radio. "I saw that there were wounded on the bus but I continued to drive on, looking straight not looking right or left. Once I got a kilometer past the area and I was out of range we took care of the wounded."
The attacks began around midday and lasted for about three hours. Israeli security forces tracked down some of the attackers and killed several in a gunbattle, military spokesman Brig.-Gen. Yoav Mordechai said. Israeli TV channels said seven assailants were killed.
Attackers came from Gaza, Israel says
Israel almost immediately said the attackers came from the Hamas-ruled Gaza Strip and made their way through Sinai, which borders both Israel and Gaza. That raised the specter of an Israeli military reprisal against the Palestinian territory.
"Today we all witnessed an attempt to step up terror by attacking from Sinai. If anyone thinks Israel will live with that, he is mistaken," Prime Minister Benjamin Netanyahu said late Thursday. "If the terror organizations think they can strike at our civilians without a response, they will find that Israel will exact a price — a very heavy price."
U.S. Secretary of State Hillary Rodham Clinton condemned what she called "premeditated acts of terrorism against innocent civilians," and said the U.S. and Israel were "united in the fight against terror."
Clinton added that the violence "only underscores our strong concerns about the security situation in the Sinai Peninsula," and urged the Egyptian government to find "a lasting solution."
The U.S. Embassy in Tel Aviv issued an "emergency message" urging U.S. citizens to avoid the area of the attack and requiring embassy employees and their families to receive approval before traveling to Israel's south.
Late Thursday, Egypt's official news agency said masked militants in pickup trucks opened fire on an Egyptian police checkpoint near el-Arish in northern Sinai, the latest security incident in the desert. There was no immediate word of casualties.
Hamas denied involvement.
The attacks, which came close together in time and location, appeared coordinated, and represented one of the boldest strikes in years against Israel. In Egypt, a senior security official denied that the attackers crossed into Israel from Sinai or that the buses were fired at from inside Egyptian territory.
"The border is heavily guarded," said a Sinai-based official who spoke on condition of anonymity.
However, security in the Sinai has deteriorated sharply since February, when longtime leader Hosni Mubarak was ousted in a popular uprising. Many Israelis saw Mubarak as a source of stability with shared interests in containing Iran and its radical Islamic proxies in the region, such as Hamas. Mubarak also upheld the decades-old peace treaty with Israel.
Last week, Egypt moved thousands of troops into the Sinai as part of a major operation against al-Qaida-inspired militants who have been increasingly active in Sinai since Mubarak's ouster. The militants have taken advantage of the security vacuum caused by the abrupt withdrawal of police forces. Authorities have blamed the militants for brazen attacks on police patrols as well as a string of bombings on a key pipeline carrying natural gas to Israel and Jordan.Interactive: Israel's border (on this page)
The attacks began around midday, when assailants targeted a packed passenger bus driving along a highway about 10 miles north of the Red Sea resort of Eilat, close to the border crossing into Sinai. About half an hour later, gunmen fired on a private car several miles away. Half an hour after that came reports that a military patrol had driven over an explosive device along the Israel-Egypt border.
Israel Radio said a vehicle had followed the bus, and two to three gunmen got out and opened fire with automatic weapons.
The vehicle fled the scene, and Israeli security forces pursued it, Israel Radio said. Channel 2 reported that two helicopters had been deployed to join the chase.
The attackers fired mortars and an anti-tank missile.
TV footage showed the bus pulled over by a red, rocky cliff. Windows and a door of the bus were shattered, and soldiers were patrolling the area on foot. Inside the bus, seats were stained with blood and luggage littered the aisle.
"We heard a shot and saw a window explode. I didn't really understand what was happening at first. After another shot there was chaos in the bus and everyone jumped on everyone else," passenger Idan Kaner told Channel 2 TV. He said the incident lasted three or four minutes until the bus was able to drive away.
The bus driver interviewed by Channel 2 did not provide details of the attack but appeared calm, smoking a cigarette in the driver's seat.
After that, an explosive device was detonated under the vehicle of a military patrol called to the scene, and a private car was also attacked.
'Large number' of assailants
Roadblocks were thrown up in the area and that entrances and exits to Eilat were sealed. Senior Israeli security officials convened in emergency session at the defense ministry in Tel Aviv.
The military said a "large number" of assailants were working in multiple squads, but it gave no specifics.
"We are talking about a terror squad that infiltrated into Israel," said Israeli military spokeswoman Lt. Col. Avital Leibovich. "This is a combined terrorist attack against Israelis."
The driver of the bus said he had seen Egyptian soldiers open fire, but Mordechai said he was not aware of any Egyptian military involvement.
Concerns about U.N. vote
The attacks by a team of apparently coordinated squads also highlighted the potential for a sharp spike in violence as Palestinians prepare to ask the United Nations to recognize them as an independent state.
Palestinian militants in Hamas-ruled Gaza have fired intermittent barrages of mortar shells into Israel for a decade, even after the Israeli military launched an offensive in the territory in late 2008. But in recent years Israel has not suffered the repeated deadly suicide bombings and shooting attacks of years past. The area of Thursday's attacks has been largely peaceful since Israel and Egypt signed a peace deal in 1979.
Palestinian leaders in the West Bank have drawn up plans for rallies in September in hopes of boosting their drive for U.N. recognition — an initiative begun after Palestinians lost faith in peace talks with Israel. Those negotiations have been frozen for most of the past three years and there is no sign the two sides can agree on conditions to resume them.
The Associated Press and Reuters contributed to this report.