With missiles launched from helicopters, Israel killed a top leader of Hamas and his three bodyguards in Gaza City on Saturday, shortly before Yasser Arafat, the Palestinian leader, nominated a critic of the Palestinians' armed uprising to a new post of prime minister.
Hamas vowed to avenge the killing, calling the target, Ibrahim Makadmah, a purely political leader. But Israeli security officials described him as "one of the central characters in the planning, approval and executing of the terrorist operations of Hamas in the Gaza Strip."
Arafat nominated Mahmoud Abbas, his deputy in the Palestine Liberation Organization, taking a step toward meeting the demands for change from Palestinian reformers, the Bush administration and Israel. But the announcement touched off an internal debate over how much power Arafat would cede to Abbas.
Saturday's events reflected the growing struggles on two fronts of this conflict _ a new rush of violence and a halting search for diplomatic avenues. Israel took the rare step of permitting a few Palestinian leaders, including some from Gaza, to cross army checkpoints to reach Ramallah for Arafat's announcement, made in a speech to the PLO's central council.
Arafat said he hoped for immediate action on a road map toward peace and a Palestinian state that was drawn up by the so-called diplomatic quartet of the United States, the United Nations, the European Union and Russia. But the Bush administration has now rebuffed its diplomatic partners and put the plan on hold until after the crisis in Iraq is resolved, administration officials said.
The PLO's central council approved Abbas' nomination Saturday night. But Abbas, who is 67 and is also known as Abu Mazen, has said he would not accept the post of prime minister unless it came with significant authority. The Palestinian legislature is expected to begin debating a definition of the new post Monday.
In his speech, Arafat affirmed his stated desire for a two-state solution to the conflict with Israel, saying he sought a Palestinian state, with its capital in Jerusalem, in the West Bank and Gaza Strip, which Israel occupied in 1967. He also urged all Palestinian factions to embrace a one-year truce initiative proposed by Egypt to protect Palestinians from "the mad plans of the Israeli government."
Aggressive pursuit of either goal would put Arafat on a collision course with Hamas, the militant Islamic group that rejects any negotiated settlement with Israel that does not end the state's existence. But the Israeli government of Prime Minister Ariel Sharon dismisses the stated positions of Arafat, regarding him as a terrorist bent on Israel's destruction.
Israel says that because Arafat will not crack down on Hamas, it has to do the work itself.
Makadmah and his guards were killed when two helicopters unleashed at least four missiles at his white Mitsubishi sedan, which was passing through a residential neighborhood in Gaza City. The car was reduced to a charred metal skeleton. Bloodstains covered the street and the second-story walls of an apartment building a few paces away.
Six bystanders were slightly wounded, Palestinians said. A large crowd quickly surrounded the car, with some men angrily denouncing Israel while others picked through the smoldering wreckage for body parts.
The Israeli military declined to comment on the helicopter attack.
The security officials said he had been linked to attacks that killed 28 Israeli soldiers and civilians.
But Hamas insisted that Makadmah had become a strictly political figure in recent years, and said it would strike back at Israeli politicians. Within hours of his death, Hamas began putting up posters that read in part, "All military choices are open now, and at the top of the list are the Israeli political leaders."
Hamas militants have long since gone underground. But senior Hamas political leaders have taken a casual attitude toward their own safety. Makadmah, a dentist, was believed to be on his way to the clinic where he worked at Islamic University when his car was struck.
Since a Hamas bombing that blew up a tank and killed four soldiers Feb. 15, the Israeli army has carried out a fierce campaign against the group in Gaza, not sparing senior leaders.
As Israeli forces wage their campaign, killing dozens in Gaza, including civilians, Hamas has repeatedly vowed retaliation. On Wednesday, a Hamas suicide bomber killed 15 people aboard a bus in the Israeli city of Haifa, and on Friday night Hamas gunmen shot dead a Jewish couple in a West Bank settlement.
Since last summer, in what it says is a campaign against terrorism, Israel has seized territory in the West Bank that was ceded to Palestinian control under the Oslo accords.
Abbas, who signed the Oslo accords on behalf of the Palestinians, is said by knowledgeable Palestinians and diplomats to regard the uprising as a disaster for his people's national aspirations. But that attitude, together with a retiring nature, have left him without much popular following.
Diplomats who have pressed for the appointment of a strong prime minister said Abbas' fate, if he accepts the new post, is partly in Israel's hands. They say that within days of his appointment, Israel should move to ease restrictions on Palestinians to enhance Abbas' credibility, and to enable him to consolidate a power base.
Arafat and Abbas have often clashed, and some officials who deal with both men say they do not particularly like each other. "This is going to be an uphill battle," said Ziad Abu Amr, a reformer in the legislature, adding in reference to Arafat, "I don't think the president is going to easily relinquish some of his powers, and probably he will view the appointment, which was forced upon him, with anxiety."