Intense fighting is continuing in the Gaza Strip, as rival armed members of Palestinian groups Hamas and Fatah battle to control key security posts.
Residents say fighting has been the worst for months
Tuesday was the bloodiest of four days of unrest in which dozens have died in gunfights and execution-style killings.
Hamas men appear to be systematically taking over Fatah-controlled buildings in northern Gaza, including the National Security Forces headquarters.
Fatah says it will boycott cabinet meetings of the unity government.
After an emergency meeting in the West Bank on Tuesday day, Fatah said it would pull out of the government if a truce could not be adhered to.
But fighting continued on Wednesday, spreading to central Gaza and Gaza City.
Gunmen fought for control of high-rise buildings serving as sniper positions and Hamas said it had bulldozed a Fatah outpost controlling Gaza's main north-south road.
North of Gaza City: Security compound seized by Hamas
North-South road: Fatah post destroyed
Gaza City: Clash at Fatah commander's house
Northern Gaza City: Mortar hits Hamas leader in Shati camp
Gaza City & Khan Younis: Protests broken up
A mortar shell hit the home of a Hamas deputy cabinet minister in the Shati refugee camp, setting it alight.
At least eight pro-Fatah men were reported killed in two separate clashes.
Frightened civilians stayed in their homes, keeping children indoors for safety, although important school exams were meant to take place this week.
Several hundred civilian protesters briefly turned out in Gaza City to call for a ceasefire, but they scattered when confronted by masked Hamas gunmen firing their weapons. One report says a protester was killed and 14 others were injured by the gunfire.
Another demonstration was broken up in similar fashion in Khan Younis, with one person injured. A pro-Fatah officer was also shot dead at a police compound.
About 200 Hamas fighters seized the strategic headquarters of the Fatah-allied security forces in northern Gaza after dark on Tuesday
They had fired mortars, rocket-propelled grenades and machine guns at the compound for several hours. At least 17 people died in the fighting.
Jeeps carrying Fatah reinforcements were sent to the compound, but they never made it through to help their 500 comrades.
"We were pounded with mortar, mortar, mortar; they had no mercy," said one Fatah fighter in remarks quoted by the Associated Press.
Correspondents say some pro-Fatah officers were frustrated by not having a coherent central command and not getting clear orders to fight back.
Many Fatah leaders have left Gaza for the West Bank after previous fighting, while Fatah strongman Muhammad Dahlan is in Egypt for medical treatment.
"There's a difference between leading on the ground and leading by mobile phone," Police Colonel Nasser Khaldi of Fatah said in comments reported by AP.
Israel, which withdrew troops and settlers from Gaza Strip in 2005, says it will not intervene in the fighting.
Hamas and Fatah agreed their seventh truce in just over a month on Monday, trying to end fighting that has claimed more than 100 lives.
There have been sporadic outbreaks of civil strife since Hamas won parliamentary elections in January 2006, ending years of Fatah domination of Palestinian politics.
The election triggered a Palestinian political and economic crisis, with international donors boycotting the government because Hamas - which they consider a terrorist group - refuses to recognise Israel and renounce violence.
Israel has refused to hand over hundreds of millions of dollars in tax, which it collects on behalf of the Palestinians.