Israeli aircraft launched an assault on the radical Islamic Jihad organization from the skies over Gaza, killing the group's overall commander and nine other militants in three fiery strikes ending early Tuesday. A fourth attack on a security post in southern Gaza killed two Hamas militants.

The heavy death toll was part of a stepped-up offensive against Gaza militants, who fire rockets into southern Israel almost daily. Islamic Jihad, a small radical group with ties to Iran, has taken responsibility for most of the barrages, including an attack this week that slightly wounded a 2-year-old Israeli boy.

Islamic Jihad acknowledged it had suffered heavy losses but said it would retaliate with suicide attacks inside Israel, threatening to unleash "a wave of martyrdom operations."

Thousands of Gazans took to the streets in funeral processions for the dead militants, whose bodies and coffins were draped with black Islamic Jihad flags. In northern Gaza, bullets from the rifles of mourners severed an electric wire that fell and injured five people, medics said.

Israeli Defense Minister Ehud Barak congratulated the army for its "successful activity" against Gaza militants.

"I hope these successes continue. At the same time we must be on our guard for the responses that may come from the other side," Barak said, speaking after a meeting with the new American military envoy to the region, James L. Jones.

Four of the Islamic Jihad militants were targeted as they emerged from morning prayers Tuesday at a northern Gaza mosque. Six others died when Israeli aircraft blasted two cars in Gaza City after nightfall Monday.

"There is no doubt that this is a big loss," Khader Habib, an Islamic Jihad leader in Gaza, told The Associated Press.

Israel has been carrying out frequent airstrikes and ground incursions into Gaza since the Hamas militant group violently seized control of the area last June. Hamas, which doesn't recognize Israel's right to exist, hasn't been heavily involved in the cross-border attacks, but Israel holds it responsible because it allows other armed groups, including Islamic Jihad, to operate with impunity.

Israeli government spokesman Mark Regev said the rocket squads have forced the army to take action. "These extremists don't want to just kill innocent civilians; they want to kill the peace process," Regev said.

The airstrikes in Gaza came a day after Palestinian President Mahmoud Abbas gained strong support for his moderate government at an international donors' conference in Paris. Donors pledged $7.4 billion (euro5.1 billion) over the next three years, far more than he expected.

Abbas is locked in a deadly power struggle with Hamas, which overran Gaza in June after routing his fighters. Abbas rules from the West Bank and has little control over Gaza.

The fundraising followed the recent relaunch of formal peace talks with Israel. Negotiations got off to a rocky start over Israel's refusal to halt construction in east Jerusalem and the West Bank — areas captured in the 1967 Mideast war that the Palestinians want as part of a future state.

On Tuesday, a top ally of Israeli Prime Minister Ehud Olmert's proposed solving the problem by swapping Israeli territory for disputed land where Jewish communities or neighborhoods have been built.

"What I propose is that we reach an agreement with the Palestinians today over the principle of settlement blocs under Israeli sovereignty and in return an exchange of territory," Vice Premier Haim Ramon said, becoming the first Israeli official to openly endorse the idea.

Abbas has already expressed support for a land swap. But in Paris, he said any swap would require Israel to hand over "the same quality and quantity of land" that it keeps, adding it was "premature" to discuss such a deal. He said settlement expansion poses a serious obstacle to Israeli-Palestinian peace talks and reiterated a call for a freeze on all settlement activity.

Israel hopes to reach a peace deal with Abbas by 2008, though officials say an agreement can't be carried out until the moderate Palestinian president regains control of Gaza. Abbas condemned the Israeli airstrikes in Gaza, but also condemned the rocket attacks as "useless."

Palestinians fired rockets and mortar shells at Israel on Tuesday morning. Two shells hit an Israeli farm, damaging a chicken coop but causing no casualties, the military said.

The air attacks, the military said, targeted militants involved in rocket fire at Israel.

The target of the first Israeli airstrike in Gaza City late Monday was Majed Harazin. The group said he was its top commander for the West Bank and Gaza, and he rarely traveled in vehicles for fear of an Israeli airstrike.

Another militant was killed in the raid, hospital officials said.

Hamas radio said the car was filled with explosives and warned people to stay away, but people crowded around the burning vehicle. Witnesses said the initial blast was followed by smaller explosions after the car was hit.

In the second airstrike, shortly before midnight, the military said it targeted a cell that was about to fire rockets at Israel. Undercover agents took part in the attack, the military said, and the leader of the cell, master rocket-maker Karim al-Dahdouh and three other militants were killed.

The third strike, early Tuesday, killed four militants. Four civilians were also wounded, medical officials said.

The fourth attack, on a Hamas security post in the southern town of Rafah, killed two members of Hamas' security force, Hamas said. The Israeli military confirmed it carried out the strike.