Israeli special forces entered an area in northern Gaza Strip and arrested four Palestinians, local sources said on Sunday.

Witnesses said that the detainees were shepherds who were herding their cattle a few hundreds of meters to the security fence that separates between Israel and Gaza in the north town of Beit Lahiya.

According to local residents, tanks rolled for nearly 100 meters into the Palestinian land and the special forces followed the tanks and advanced deeper before finding the shepherds.

An Israeli helicopter opened machine gun fire during the quick incursion apparently to cover up the troops.

Prior to the incursion, a sound of an explosion was heard and the residents said it was a bomb that went off near the fence.

(Xinhua News Agency September 7, 2009)