Seven people were killed and 14 others were wounded Tuesday when Palestinian terrorists dressed in Israeli army uniforms ambushed an Israeli bus, setting off an explosion to stop the vehicle and then opening fire on the passengers as they fled. Three of those killed were from the same family.

The ambush was the first deadly attack on Israeli civilians since June 20, and it occurred hours before officials from the United States, Russia, the European Union and the United Nations met in New York to discuss ways of ending more than 21 months of violence and easing the humanitarian situation in Palestinian territories.

Among the dead was an 8-month-old girl, her father and her grandmother, Israel Radio reported.

Several militant groups rushed to claim responsibility for the attack, which was nearly identical to one on Dec. 12 that killed 11 people in the same place — at the entrance to the ultra-Orthodox Jewish settlement of Emmanuel, between the West Bank towns of Qalqilya and Nablus.

Witnesses reported hearing a loud explosion as the armored bus, traveling a regular route between Emmanuel and another ultra-Orthodox town inside Israel, Bnei Brak, neared the settlement entrance.

The blast was followed by smaller grenade explosions and bursts of automatic fire that lasted for several minutes. The witnesses said three to four gunmen dressed in Israeli army uniforms opened fire on the passengers as they tried to escape.

The militants fled and were pursued by army helicopters.

Rachel Gross, a 17-year-old high school student, said the bus lurched into the air when the bomb went off. "I got down under the seats, as fast as I could, because the terrorists began firing bursts and throwing grenades, it went on and on it seemed like eternity," she said while visiting the wounded at a hospital. She was not hurt.

Gross said that when she got up, she saw an unexploded grenade on the seat in front of her. The doors of the bus were jammed shut, she said, and rescue workers came in through the windows.

Moshe Avraham Cohen, in charge of security for the settlement, said he was in his office when he heard the explosion, then drove to the scene in his armored car, only to find it eerily quiet.

"I opened the (bullet proof) car door a bit. Suddenly I saw three soldiers at the side of the bus. I was happy, seeing they had already arrived. I was going to ask them if they needed help, and before I could get the words out they shot at me," he said.

He said he sped away.

Taxi driver Yitzhak Yazdi said he heard the explosion and saw stones flying over the road as he neared the scene, plumes of smoke billowing 30 feet high. "I saw two terrorists who were running away from the road and they hid behind a rock," he said.

The ambush killed seven people and wounded 14, three of them seriously, police and hospital officials said. Among the wounded was a 2-year-old, two 12-year-olds and a pregnant woman, Israel TV said. The pregnant woman was shot in the head, said Ron Nachman, mayor of nearby Ariel. Israel radio reported that her baby was delivered later Tuesday, and both mother and child were in critical condition.

In more than 21 months of fighting, 1,758 people have been killed on the Palestinian side, and 572 on the Israeli side, including those who died in Tuesday's attack.

The most recent fatal attack on Israeli civilians occurred June 20, when a gunman killed five Israelis in the Jewish settlement of Itamar, near Nablus in the northern West Bank.

The lull in attacks was widely seen in Israel as evidence that the policy of reoccupying the Palestinian Authority's autonomous zones was the best method for preventing attacks on Israelis.

"If we had not been there, we would have had 12, or 10 attacks rather than one," said Ranaan Gissin, a spokesman for Israeli Prime Minister Ariel Sharon.

He said that until the Palestinians unify their security services and use them to "eradicate terrorism ... we will have to be deployed in those areas where we are in order to stop this wave of terrorist activity."

Foreign Minister Shimon Peres told Israel TV that he canceled a meeting set for Wednesday with senior Palestinian officials because of the attack.

The military wing of Hamas, Izzadine al-Qassam, claimed responsibility in two telephone calls to The Associated Press in Jerusalem, saying the militants responsible were safe in the Nablus area.

However, two other groups also claimed responsibility: the Syria-based Democratic Front for the Liberation of Palestine said it carried out the attack; and Abu Dhabi TV in the United Arab Emirates said the Al Aqsa Martyrs Brigade, affiliated with Palestinian leader Yasser Arafat's Fatah movement, said the same.

It was considered unlikely that Israel would stage a military retaliation in response to the attack during the talks in New York.

The Palestinian Authority condemned the attack in a statement. The Palestinians frequently condemn homicide attacks inside Israel — but not those in the West Bank and Gaza, arguing that Palestinians have a legitimate right to resist Israeli occupation.

President Bush condemned the attack, White House spokesman Ari Fleischer said. "This underscores the importance of focusing on peace and working with leaders in the Palestinian Authority who are dedicated to peace," he said — an apparent reference to the U.S. position that it won't deal with Arafat anymore.

Fleischer said that since Bush's June speech calling for Palestinian reforms and a new leadership, "there have been some interesting rumblings from within the Palestinian Authority about the direction they would like to go in the future."

Arafat outlined reforms he has proposed in a letter to the Bush administration, but in an interview with The Associated Press last week, he refused to step down. He admitted, however, that he hadn't decided whether he would be a candidate in January elections.

The Associated Press contributed to this report.