In simultaneous terrorist attacks on Israeli tourists Thursday, three homicide bombers killed 12 other people and wounded 80 at an Israeli-owned hotel, and militants fired at least two missiles at — but missed — an Israeli passenger jet taking off from Mombasa airport.

Two people were detained and were being questioned in the Kenya attacks but have not been formally charged, according to the duty officer at police headquarters in Nairobi. The officer, who spoke on condition of anonymity, said they were detained in the Indian Ocean port city of Mombasa but gave no further details.

A previously unknown militant group calling itself the Government of Universal Palestine in Exile, The Army of Palestine claimed responsibility, but Kenyan, Israeli and U.S. officials said Usama bin Laden's terrorist network couldn't be ruled out.

In a fax to news organizations in Beirut, Lebanon, the militant group that claimed responsibility said the attacks were timed "to strike at Israeli interests" on the eve of the anniversary of the Nov. 29, 1947, decision by the United Nations to partition Palestine and allow creation of a Jewish state.

It was not immediately possible to verify the statement's authenticity and Palestinian officials denied any connection with the attacks.

Israeli government adviser Zalman Shoval said Al Qaeda's past activities in East Africa and the nature of the attacks pointed to the group, which carried out almost simultaneous bombings to the U.S. embassies in Kenya and Tanzania in 1998 that killed 231 people — including 12 Americans — and injured about 5,000.

If Al Qaeda was responsible for the attack, it would be the first by the terrorist group on Israeli interests. There have, however, been indications the organization might begin targeting Israelis to win support among Muslims angry over Israeli actions against Palestinians.

Dia'a Rashwan of Egypt's Al-Ahram Center for Political and Strategic Studies said Al Qaeda operatives can move among the region's Muslim population without attracting much attention and the nation's underpaid and understaffed police force has difficulty tracking them down.

"We can't rule out the group that struck at us in 1998," Kenyan Vice President Musalia Mudavadi said, adding that national intelligence had received reports the country could be targeted again by terrorists.

Israel vowed to track down those behind the attacks and Prime Minister Ariel Sharon put the Mossad spy agency in charge of the investigation. The agency hunted down and killed nearly all the Palestinians believed responsible for kidnapping and killing 11 Israelis during the Munich Olympics in 1972.

"Our long arm will get those who carried out the terror attacks. No one will be forgiven," Sharon said. Israeli Defense Minister Shaul Mofaz added: "If anyone doubted that the citizens of the state of Israel cannot stand up to the killers of children, this doubt will be removed."

In apparently unrelated violence, six Israelis died in another bloodletting at home as gunmen open fire on a bus station and a crowd waiting to vote in the Likud Party primary in northern Israel.

Israeli troops and medics began arriving in Mombasa to quickly evacuate the wounded and Israeli tourists. An Israeli plane left Mombasa early Friday with 80 passengers, including 10 lightly injured.

The deadly attack at the beach-front Paradise Hotel, some 15 miles north of Mombasa, occurred about 8:35 a.m. as new guests were checking in and others were eating breakfast.

According to witnesses, a green four-wheel drive carrying three men smashed through the main gate to the sprawling hotel compound — a collection of buildings surrounded by palm trees that stretch to a nearby sandy white beach.

One man jumped from the vehicle, sprinted into the reception area and detonated a bomb, while the others detonated a bomb in the vehicle.

Police said they didn't know anything about earlier reports by hotel staff who said they saw a light plane circle over the hotel and drop three packages at the time of the explosion.

The huge blasts shattered windows and masonry along the front of the hotel, incinerated vehicles parked nearby and set fire to grass roofs of the outbuildings, reducing their wooden frames to smoldering hulks. Stone walls were all that remained of the lobby.

The victims were three Israelis, including two teenage brothers from a Jewish settlement on the West Bank, and nine Kenyans believed to be hotel staff, police spokesman King'ori Mwangi said. The Israeli newspaper Haaretz on its Web site said the third Israeli victim was a 60-year-old man from the Tel Aviv suburb of Raanana.

The three bombers were not identified.

About five minutes before the hotel attack, two missiles streaked by an Israeli-owned Boeing 757 as it left the Mombasa international airport. The aircraft, owned by the Arkia charter company, landed safely about 5 hours later in Tel Aviv, Israel. None of the 261 passengers and 10 crew members was hurt.

Late Thursday, the first of about 150 Israeli troops and army medical personnel began arriving in Mombassa to treat the wounded and evacuate them and all Israeli tourists in the area, estimated at about 140, said Ami Mehl, deputy information director for the Israeli Foreign Ministry.

"They've lost everything," Mehl said of the tourists. "Some lost families and some have lost everything but what they were wearing."

He said the operation, which included two passenger jets and four transport planes, would be completed in about 12 hours.

The targeting of Israeli tourists in Kenya and a shooting spree by two Palestinian gunmen that killed six Israelis at a polling station in northern Israel overshadowed a Likud Party leadership primary in which Sharon defeated Foreign Minister Benjamin Netanyahu.

The hotel attack in Kenya also was grimly reminiscent of last month's bombing on the Indonesian resort island of Bali, in which more than 190 people, mostly foreign tourists, were killed.

"It was a big blast. I was thrown to the ground and the windows shattered," said Zainul Jeddha, a Kenyan who was in her room on the fourth floor. "There was screaming, there was crying, it was chaos."

Police said the missiles were fired at the plane from a white all-terrain vehicle about one mile from the airport and three or four Arab-looking men were seen leaving the area in the van. Investigators found two missile casings near the airport.

At the hotel, seven charred bodies lay strewn in the lobby before Red Cross workers put them in body bags and removed them. All that was left of the attackers' vehicle was a couple of suspension springs.

A distraught survivor marked a small piece of burnt hair and skull with an index card so the remains could be properly buried under Jewish law.

Hundreds of people massed outside the hotel's gates as Kenyan authorities sifted through the wreckage. Tour buses ferried survivors to other hotels in the area.

Rebecca Zevi, 30, an Israeli who was working at the hotel, said she was in her room when the explosions occurred.

"All the glass shattered. I ran to see what was happening. There was screaming," she said. "I don't know why this happened to us."

President Bush denounced the violence and offered U.S. help in the investigation.

"Today's attacks underscore the continuing willingness of those opposed to peace to commit horrible crimes," Bush said. "The United States remains firmly committed, with its partners around the world, to the fight against terror and those who commit these heinous acts."

The State Department issued an advisory warning Americans in Kenya to exercise "extra caution" at hotels, tourist locations and urban areas, especially in coastal regions.

The 15-nation European Union also said the attacks underlined the need "for international cooperation against terrorism in all its forms." Germany urged its citizens to avoid nonessential travel to Kenya and France recommended its citizens practice "extreme vigilance" in this country.

The Indian Ocean coast of Kenya, a nation of 30 million people, is a predominantly Muslim region, and is a popular international tourist destination.

The Associated Press contributed to this report.