Four Palestinians have been killed in an Israeli helicopter strike in Gaza City.

Among the dead were two militants from Izz-el-Deen al-Qassam, the military wing of the Islamic fundamentalist group Hamas, relatives said.

Apache helicopter gunships fired missiles at a car thought to hold members of Hamas.

Two of the dead were identified as Wahid Al-Hams and Ahmed Shtawi, confirmed Hamas members.

Palestinian Information Minister Nabil Amr condemned the attack: “This shows that Israel is pursuing war against the Palestinian people. This operation coincides with the measures that the Palestinian Authority is undertaking to restore calm.

We urge the United States and the quartet to immediately intervene to stop this war,” ,”Mr Amr said.

Israel’s has stepped up retaliation strikes after a suicide bomber killed 21 people in the Jerusalem bus attack last week.

Israel assassinated senior Hamas leader Ismail Abu Shanab on Thursday, in a missile strike in the Gaza Strip.

Israel’s army chief, Moshe Yaalon pinpointed Hamas as “potential targets for liquidation.”

The US-backed “road map” for peace in the Middle East appears imperilled after Hamas said the seven-week long ceasefire would no longer be observed.

Israel wants the Palestinian Authority to suppress militant activity but some Palestinian security chiefs fear such action would precipitate all out civil war.

Separately, Palestinians have begun to close down arms smuggling tunnels between Egypt and the Gaza Strip and deployed security forces to stop rocket attacks on Israel, in a bid to restart the stalled peace plan.