Hamas militiamen's efforts to break up anti-government protests sparked running street battles across the Gaza Strip that killed eight people in the worst internal Palestinian violence since Hamas took power.
Militants from the opposition Fatah group on Sunday retaliated by torching the Palestinian Cabinet building in Ramallah, attacking Hamas offices throughout the West Bank, kidnapping a Hamas official and threatening a mass strike.
The spasm of violence dampened already fading hopes for the creation of a national unity government between the two groups that could and crippling economic sanctions.
The fighting continued throughout the day and sent schoolchildren and other civilians in downtown Gaza City fleeing for cover.
"This is forbidden in Islam, we are in the holy month of Ramadan," said Majed Badawi, 33, who managed to escape uninjured after his car was caught in the crossfire. "It's a shame on Hamas, who call themselves real Muslims, and a shame of Fatah as well. Why are they fighting and over what? We are victims because of both of them."
Late on Sunday, Interior Minister Said Siyam ordered the Hamas militia off the streets, ministry spokesman Khaled Abu Hilal said.