The Israeli raids early on Saturday left at least 17 Palestinians wounded, according Gaza medics and eyewitnesses. They said the sites targeted included two camps within Gaza City run by the Ezzedine al-Qassam Brigades, the military wing of the Islamist movement Hamas, which rules Gaza.

Two similar raids by Israeli warplanes on Friday had left two Palestinians dead and four wounded, they said.

The Israeli army in a statement issued early on Saturday said one of its planes had also targeted a "terrorist group in northern Gaza just after the group launched a rocket that hit the Ashkelon region."

Gazan officials said a fourth Israeli air strike had occurred near the southern Gaza city of Khan Yunis.

Israeli officials later said 18 rockets had been fired overnight toward Israel. One had struck the town of Sderot, wounding a man in the neck as he tried to enter a concrete shelter. Six rockets had been intercepted by an Israeli defence system.

In Gaza there was no claim of responsibility for the rocket fire on Saturday, but a security source quoted by Reuters news agency said the missiles were launched overnight by members of a fringe Salafist group sympathetic to al Qaeda. It had lost two members in Friday's air raids by Israel.

Truce in doubt

The violence came despite a tenuous Egyptian-brokered truce between Israel and Hamas that was announced on Wednesday by Hamas' military wing, which added that other groups in the strip had promised to abide by the truce. Israel did not formally comment on the reported deal.

Between Monday and Wednesday some 130 rockets and mortar rounds were fired at Israel. One of them hit a border police post, wounding four people. Israel said the lives of a million Israelis had been disrupted as civilians sought shelter.

Israel said its air raids on Gaza were "in no way related" to an incident on Monday on Israel's Sinai border with Egypt, where gunmen carried out an ambush, killing an Israeli citizen. Two of the gunmen were killed.

Five years have passed since Hamas seized Gaza in a military struggle with its secular rival Fatah, the Western-backed group once headed by the late Yasser Arafat. Hamas won parliamentary elections in 2006.

ipj/sb (AP, AFP, Reuters)