GAZA, April 17: An Israeli helicopter missile strike on a car in Gaza City on Saturday killed top Hamas leader Abdel Aziz al Rantissi.

Witnesses said two of Mr Rantissi's bodyguards were also killed in the attack in which two missiles were fired.

The air strike occurred hours after an Israeli border policeman was killed by a Palestinian suicide bomber at the Erez crossing on the Israeli-Gaza border.

Medics said Aziz Rantissi, 56, Hamas's leader in the militant group's Gaza Strip stronghold, was rushed to a hospital in critical condition after the attack. Sources said he had been wounded in the head with shrapnel.

Hundreds of Hamas members and supporters flooded to the hospital after news of the Israeli raid.

A crowd of Palestinians swarmed around the wreck of the white car, pulling out what appeared to be fragments of clothing.

Hamas, which has been behind scores of suicide attacks against Israel and has pledged to destroy the Jewish state, issued an immediate vow of revenge.

"Israel will regret this. Revenge is coming," said a senior Hamas leader at the hospital.

"This blood will not be wasted. It is our fate in Hamas and it is our fate as Palestinians to die as martyrs. The battle will not weaken our determination or break our will," Ismail Haniya told reporters.

The killing of Mr Rantissi occurred against the backdrop of Israeli Prime Minister Ariel Sharon winning US backing for a unilateral Gaza pullout plan.

Palestinian anger has mounted over President George Bush's related decision this week to allow Israel to keep some parts of the West Bank.

"We condemn in the strongest possible terms this Israeli crime and state terror," said a senior member of Palestinian President Yasser Arafat's Palestinian Authority.

"It is evident now to the world that the Palestinian people need international protection more than ever," minister Saeb Erekat said.

Mr Rantissi, a co-founder of Hamas, had become one of its two main leaders since Israel's killing of spiritual head Ahmed Yassin in Gaza on March 22.

Israel has been vowing to kill leaders of Hamas because of its attacks against the Jewish state.

It tried to kill Aziz Rantissi, public face of a Palestinian militant group that normally stays in the shadows, last June.

On that occasion he and his teenage son were wounded in a helicopter missile strike on his car, also in Gaza City.

Mr Rantissi had long depicted himself as a Hamas politician with no links to the military wing.

But Israel had refused to accept the distinction, accusing him of being a top decision-maker on attacks and of using his media role to incite violence.

With Mr Rantissi filling the role of Hamas spokesman, camera crews from around the world have trooped to his modestly furnished living room to hear him issue vows of revenge, often in calm, even tones, for Israel's killing of militants.

SUICIDE BOMBING: The attack on the Israel-Gaza border, in which the Israeli Israeli soldier was killed along with the Palestinian suicide bomber, also left two Israeli soldiers and a guard wounded.