Israel on Monday continued raids into the Gaza Strip for the third day, bringing more casualties in the unprecedented offensive into the Hamas-controlled territory.

In return, Palestinian militant groups fired rockets into Israel from Gaza, killing an Israeli resident of Ashkelon, a coastal city in northern Israel.

Palestinians look at a destroyed mosque after an Israeli air strike in Jabalya refugee camp in the northern Gaza Strip Dec. 29, 2008. Israeli aircraft attacked Hamas targets in the Gaza Strip for a third day on Monday and militants launched a fatal rocket attack on Israel in defiance of an offensive that has killed more than 300 Palestinians. (Xinhua/Reuters Photo)

The attack mainly targeted Hamas-run security establishments and police stations, with some mosques and houses being also hit by the now-and-then airstrikes.

"The number of martyrs is 310 and the wounded people who are now in hospitals is more than 800, many of whom don't find vacuum beds," said Mo'aweya Hassanein, director of emergencies at Gaza health ministry.

A Palestinian man carries the body of his 4-year-old daughter Dena Balosha during the funeral for her and her four sisters in Jabalya refugee camp in the northern Gaza Strip Dec. 29, 2008. (Xinhua/Reuters Photo)

In the latest strikes that involved civilian fatalities, five sisters, aged between four to 15, were killed when Israeli F16 warplanes hit a mosque near their house in Jabaliya refugee camp in northern Gaza Strip, witnesses and medical sources said.

The witnesses said the bombardment destroyed the two-story mosque, located between houses in the most densely populated refugee camps in the Gaza Strip. They added that the simple house of Anouar Balousha was very close to the mosque and many flying debris fell in the house, killing his five girls.

Earlier, Israeli warplanes attacked and destroyed several buildings in the Islamic University of Gaza. The installation that harbors the scientific labs and another building in the female sector of the campus were the targets.

In the morning, Israeli gunboats fired several missiles on Gaza coast, targeting fishing boats in Gaza sea port.

Meanwhile, in addition to the fatality, tens of Israelis were also wounded and suffered from shock in Ashkelon. In a statement sent to media, Hamas claimed responsibility for the attack, sayingit hit the city with a Soviet-made Grad missile.　

Editor: Yan