Four Hamas followers escaped unharmed when an unmanned drone fired two rockets on a car near the southern Gaza town of Khan Yunis, with witnesses saying that they had fled seconds before one slammed into the vehicle.

"The Israeli air force targeted a mortar shell launcher and a vehicle carrying additional mortar shells, including a launcher that was used to fire at Israeli targets," an Israeli military spokesman said.

The Islamist fundamentalist movement Hamas said it later fired three rockets at Jewish settlements in the southern Gaza as an "answer to the Israeli targeting of the group from the Ezzedine al-Qassam Brigades", referring to its armed wing.

The air strike came one day after two Palestinians and a Chinese labourer were killed in a Palestinian militant attack on a Jewish settlement in the southern Gaza Strip, claimed by Hamas and Islamic Jihad.

That attack had followed the death of three Palestinians at the hand of the army, placing unprecedented strain on a de facto truce observed by militants since late January.

Abbas and Israeli Prime Minister Ariel Sharon, who are set to meet again on June 21 declared an end to hostilities at a landmark summit in February.

The Palestinian leader appealed for calm from all sides, while also condemning the Israeli strike.

"This raid cannot be justified as it sabotages the calm," he said on his arrival in Gaza to meet Hamas and other factions for talks about "our national interests."

Israeli Defence Minister Shaul Mofaz later held talks with Palestinian interior minister Nasr Yussef in a bid to "preserve the calm," a spokesman for Yussef said.

The recent spike in violence has prompted renewed calls from within the Israeli government to postpone the planned pullout from Gaza Strip which is due to start in mid-August.

Health Minister Danny Naveh said the pullout could not take place until the likes of Hamas had been brought to heel and that Israel should stop holding back on largescale military operations just to please Abbas.

"Israel cannot remain with its arms crossed. The Tsahal (Israeli army) has the necessary means to act," said the hawkish minister.

But Sharon insisted there were no grounds to delay the withdrawal which has caused major ructions within his main governing Likud party.

"There are those who hope that the disengagement will not be carried out. I want to say unequivocally that it will be carried out on schedule," Sharon told the ministerial commission tasked with planning the pullout.

Sharon is also facing criticism over the government's preparations for the 8,000 settlers who are to be uprooted. Few have received compensation or found permanent new homes, while a decision yet to be made over whether to demolish their old houses.

Deputy Prime Minister Shimon Peres, leader of the left-of-centre Labour party and a member of the committee planning for the pullout, said "final decisions need to be made right away".

For his part, Abbas urged Israel to sanction the reopening of Gaza's airport and a "safe passage", which enables free movement of people and goods to and from Gaza and the West Bank, after the pullout.

He made the appeal during talks with James Wolfensohn, the Middle East diplomatic quartet's special envoy for Israel's disengagement project.

Visiting British Foreign Secretary Straw, whose country is due to take over the revolving presidency of the European Union later this year, said London would do "everything" in its power to make a success out of the Gaza pullout.

Palestinian officials said Abbas's talks in Gaza would also focus on his decision last week to delay indefinitely the first Palestinian parliamentary elections in nine years, which had been scheduled for July.

Hamas, preparing to contest its first legislative elections, has fiercely denounced the move. It had hoped that a strong showing in the ballot would secure its entry into the political mainstream.

Straw however denied that electoral success for Hamas would see it removed from a terror blacklist. Like the rest of the EU and the United States, Britain does not officially sanction talks with Hamas.

"The fact that a terror organisation stands in elections doesn't mean it ceases to be a terror organisation. Hamas will stay on that list until it has renounced terrorist violence in action as well as in words," he said.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.