Hamas gunmen overran the headquarters of a Fatah-allied security force in northern Gaza, killing at least 17 in a key victory in what is rapidly developing into a full-fledged civil war.
Battles over security positions spread to central Gaza in the predawn hours on Wednesday, and gunmen fought for control of high-rise buildings in Gaza City.
The fighting took the conflict from the level of street skirmishes to pitched battles between heavily armed forces. Better-trained Fatah forces displayed lack of leadership and motivation against the gunmen of the Islamic Hamas, and in some cases were outgunned.
Frightened civilians were trapped in their homes. "I don't know what to do to comfort my chidren," said Wafa Jaber, a mother of five pinned down by gunfire in her apartment.
Dozens have been killed since Monday, and two more people died of wounds on Wednesday.
The power struggle escalated further when Fatah decided to suspend the activities of its ministers in the government it shares with Hamas. In an emergency meeting in the West Bank, the movement warned it would pull out of the government if the fighting doesn't stop, said Nabil Abu Rdeneh, an aide to Fatah's leader, Palestinian President Mahmoud Abbas.
The confrontations have turned increasingly brutal in recent days, with some killed execution-style in the streets, others in hospital shootouts or thrown off rooftops.