Israeli-Palestinian fighting flared in the Gaza Strip, with 11 militants killed and both rival movements, Hamas and Fatah, calling on their people to fight back, overshadowing their bloody infighting that ended just three weeks ago.
Israel called in aircraft, tanks and bulldozers on Friday to press its military campaign against Gaza rocket squads, while militants laid mines and fired mortars at soldiers at a main Gaza-Israel passage.
After sweeping out its Fatah rivals in a lightning campaign last month, the Islamic militant Hamas is trying to solidify its regime in Gaza, administering the crowded, chaotic, poverty-stricken territory.
It has initiated few attacks against Israel, but also has not stopped other groups from firing rockets at Israeli towns almost daily -- provoking Israeli military action and drawing Hamas forces in.
The first clash erupted close to the Bureij refugee camp in the central Gaza Strip, a site of frequent clashes between gunmen and the Israeli army.
Witnesses reported a heavy exchange of fire as Israeli tanks and bulldozers moved in and soldiers took positions on rooftops. Hamas and Islamic Jihad militants hit back with small arms fire, laid mines in front of the soldiers and fired mortars at the Erez passenger crossing between Israel and Gaza.
Two of the mortars landed on the Israeli side of the passage, which has been closed to most traffic since Hamas wrested control of Gaza last month, the army said. No one was hurt, but the mortar shells ignited fire in a road at the crossing, the army said.