The 32-year-old Hamas commander, who had four children, was hit by a single shot in the neck, fired from the neighbouring Ganei Tal settlement, as he sat on the roof of his house. He was the eighth victim in a new round of killings of Palestinian fighters after a nine-month break.
The resumption of "targeted killings" was provoked by last Tuesday's suicide bombing in the Israeli resort of Netanya and by Palestinian rocket and mortar fire on Jewish civilian targets inside the Gaza Strip and across the border. Two settlers were seriously wounded yesterday in Nevei Dekalim, near Khan Yunis, in apparent retaliation for the killing of Sa'id Siyyam.
A month before Israel plans to evacuate all 21 Gaza settlements, the ceasefire agreed at the Sharm el-Sheikh summit in February is crumbling by the hour. Fearing that the return to violence could jeopardise the disengagement, Condoleezza Rice, the US Secretary of State, is planning an emergency visit this week. Egypt has sent a high-level security team to Gaza to try to restore calm.
Israel, which massed a large armoured and infantry force on the Gaza border at the end of last week, yesterday gave Mahmoud Abbas, the Palestinian President, 24 hours to rein in Hamas and other militias. Shaul Mofaz, the Defence Minister, warned the Palestinian Authority that otherwise Israel would launch a large-scale ground operation to stop all shelling until the Israeli settlers have left Gaza. Ariel Sharon, the Prime Minister, told his cabinet: "I have instructed the security establishment to take all measures, without restrictions, to stop the wave of terrorism and to strike at the terrorist organisations and the terrorists. We are greatly interested in reaching a diplomatic settlement, but this is impossible while terrorism runs amok along our borders."
Palestinian police exchanged automatic fire with Hamas gunmen in Gaza over the weekend.
In a televised speech on Saturday, Mr Abbas said the ceasefire was a high Palestinian interest. "We will not allow anyone to violate it," he warned.
But Israel was not satisfied that the Palestinian leader was doing enough. His security forces have yet to prove they are sufficiently strong and motivated for the task. Police took the symbolic step yesterday of removing green Hamas flags from electricity poles, but would not risk entering militia strongholds in the refugee camps.
Hamas remains defiant. Its gunmen shot Ra'id Abu Haloub in the legs on Saturday because the police commander had ordered his men to open fire on the militants launching rocket attacks. Musheer al Masri, a Hamas spokesman, said: "This is a dispute between those who accept the dictates of the United States and the Zionists, who urge them to shoot at our fighters, and the forces of resistance who believe in resistance as a strategic choice."
Mr Sharon is now waging a war on two fronts: against Palestinian gunmen, who want to celebrate the withdrawal as a victory for armed resistance, and against his own right-wingers, who still hope to force him to cancel it and are planning a protest march today. After hundreds of settlers and supporters clashed with soldiers and police on the Gaza border at the weekend, Mr Sharon ordered troops to use "all force" to stop them entering the strip, closed by military order last week. Two soldiers refused to disperse the rioters and fled into one of the settlements. Seven others were arrested for disobeying orders. The army is threatening to disband their unit, which doubles as a Talmudic study group.Reuse content