JERUSALEM -- Israel on Wednesday said it had foiled an "advanced" al-Qaida plan to carry out a suicide bombing on the U.S. Embassy in Tel Aviv and to bomb other targets, in what analysts said was the first time the global terror network's leadership has been directly involved in plotting an attack inside Israel.
The Shin Bet intelligence agency said it had arrested three Palestinians who allegedly plotted bombings, shootings, kidnappings and other attacks. It said the Palestinian men, two from Jerusalem and one from the West Bank, were recruited by a Gaza Strip-based operative who worked for al-Qaida leader Ayman al-Zawahri.
The State Department said the United States was not yet able to corroborate the Israeli claims.
While a number of groups inspired by al-Qaida have carried out attacks against Israel before, this appeared to mark the first time an attack was directly planned by al-Qaida leaders.
The Shin Bet said the Palestinians planned on attacking a Jerusalem conference center with firearms and then killing rescue workers with a truck bomb. It said al-Qaida also planned on the same day to send foreign militants to attack the U.S. Embassy in Tel Aviv, using explosives supplied by the Palestinians.
Five men, whose identity and nationality were not disclosed, were to fly into Israel with fake Russian passports to attack the American embassy, the agency said. It was not clear where the men are located.
The Palestinian operatives planned more attacks, it said, including shooting out the tires of a bus, then gunning down passengers and ambulance workers.
The agency said the plot was in "advanced planning stages," but gave no further information on how close the men were to carrying it out. It said the Palestinians from Jerusalem, arrested in the past few weeks, had used their Israeli resident cards to gather intelligence on targets.
A number of al-Qaida-inspired groups have carried out rocket attacks from Gaza and Egypt's Sinai Peninsula, as well as West Bank shootings. Israeli intelligence calls these groups part of a "global jihad" movement.
Aviv Oreg, a former head of the Israeli military intelligence unit that tracks al-Qaida, said the plot marked the first time it has been directly tied to an attempted attack in Israel. "This is the first time that Ayman al-Zawahri was directly involved," he said. "For them, it would have been a great achievement."
The Shin Bet said the three suspects made contact with al-Qaida over the Internet. It said they planned on traveling for training in Syria, where various jihadist groups are battling President Bashar Assad's forces.
Mr. Zawahri's location is unknown, but he was last thought to be in Pakistan. He is the subject of an intense manhunt, and experts say he is not believed to go online personally or to pick up the phone to discuss terror plots.
Last year, a threat that began with a message to Mr. Zawahiri from the Yemen-based al-Qaida in the Arabian Peninsula led to closures of embassies across the Middle East and Africa, a U.S. official said then. The message essentially sought out Mr. Zawahri's blessing to launch attacks.
Al-Qaida-inspired groups are on the rise in the Gaza Strip, which is run by the Islamic militant group Hamas. These groups accuse Hamas of being too lenient because it has observed cease-fires with Israel and has stopped short of imposing Islamic religious law, or Shariah, in Gaza.
In the West Bank, Israel and the Palestinian Authority of Western-backed Palestinian President Mahmoud Abbas have cracked down on Islamic militants. Three Salafis, members of a movement advocating a hard-line interpretation of Islamic law, were killed in a shootout with Israeli soldiers in the West Bank last November.
In Washington, State Department spokeswoman Marie Harf said U.S. investigators and intelligence officials were not yet able to corroborate the Israeli information and declined comment on specifics of the case.
She said there were no plans to evacuate the embassy in Tel Aviv, and she was not aware of stepped-up security measures there after the arrests.
Earlier Wednesday, an Israeli airstrike killed a key Gaza militant who was behind a recent wave of rocket attacks on Israel, the military and Palestinians said. The Israeli military said it targeted Ahmad Zaanin, an operative in the Popular Front for the Liberation of Palestine, ''to eliminate an imminent threat to the lives of Israeli civilians."