Thirteen Palestinians were killed since the beginning of Saturday in the continuing Israeli military operations in Gaza Strip, bringing the total death toll to 1,205.

A number of fatalities was reported when Israeli artillery fired several phosphorus shells at a UN-run school used to harbor displaced families in northern Gaza Strip town of Beit Lahiya, according to witnesses, medical sources and a spokesman of UN Relief and Works Agency.

"Ambulance crews evacuated the bodies of two young brothers and their critically injured mother from the school," said Mu'awia Hassanien, a health ministry official. He added that 13 others were seriously burnt.

Meanwhile, the Israeli aerial and artillery bombing on Gaza continued, intensifying the strikes at the northern and southern ends of the strip.

According to witnesses, another attack by white phosphorus shells targeted al-Karama district in northwest Gaza city, killing four people.

Hassanien said it is difficult to identify the four dead because the chemical material turned their bodies into white bones.

To the west of al-Karama area, four Palestinians were wounded when Israeli gunboats opened fire towards the shore.

The Israeli artillery focused its fire at border areas in Gaza Strip, with missiles landing at densely-populated areas, such as the Jabaliya refugee camp and eastern Gaza City, from time to time.

The Israeli tanks and ground troops, which entered Gaza on January 3, still divide the coastal strip into three isolated parts, with the tanks pushing in and out at the Hamas-controlled territory.

According to statistics provided by Gaza hospitals, 410 children, 108 women and 113 elderly people were among the dead. The number of wounded people stands around 5,300.