The Associated Press

GAZA CITY, Gaza Strip -- An Israeli helicopter fired rockets into a car carrying Palestinian militants Thursday, killing at least two and wounding 35 bystanders. Israel said the target was Hamas' chief bombmaker, and there were conflicting reports about whether he was killed.

Hamas insisted bombmaker Mohammed Deif was alive, but the Islamic militant group threatened to strike everywhere in Israel to avenge the air strike. Israeli police sources and media reports said Deif was killed.

A senior Palestinian security official, speaking on condition of anonymity, said Deif was moderately wounded in the attack and was in hiding. The official said Palestinian leader Yasser Arafat was informed of the situation.

None of the claims could be independently confirmed.

Deif's death would likely trigger massive retaliation by Hamas, which has carried out scores of suicide attacks in Israel. In 1996, after Israel killed Deif's mentor, Yehiyeh Ayyash, Hamas responded with four suicide bombings that killed dozens of Israelis.

Deif has topped Israel's wanted list for several years, and escaped an Israeli air strike earlier this year. Israel says Deif was Ayyash's successor. Israeli officials said Thursday he is believed to have had a hand in all major Hamas bombings since then. He is known to have trained bombmakers who were later sent to the West Bank.

For some time, until December 2000, Deif was in Palestinian custody. The Palestinians said at the time that he escaped, while Israeli officials said he was set free by his jailers.

A leader of the violent Islamic group, Abdel Aziz Rantisi, said Deif survived Thursday's air strike. Hamas sources identified two dead men as members of Hamas, Abdel Rahim Hamdan, 27, and Issa Abu Ajra, 29. Israeli TV reports said two bodyguards of Deif were killed.

The reports said there was a third body -- apparently that of Deif. The bodies were badly disfigured, making identification difficult.

Rantisi said Hamas would avenge the missile attack. "We will hit Tel Aviv. We will hit everywhere," he said.

A senior Israel official, speaking on condition of anonymity, confirmed that Deif was the target but said it was not known if he was killed. The military had no immediate comment. Israeli police sources said they had been told by the military that Deif was dead, and that they had been asked to prepare for possible revenge attacks.

In the past two years, 76 wanted Palestinians and 52 bystanders have been killed in targeted Israeli attacks, including several in rocket attacks on cars carrying suspected militants.