At least seven people have been injured in the Gaza Strip in a fresh wave of violence between armed militia groups and the Palestinian security forces.
Gunmen stormed the main government compound in Gaza, opening fire randomly in the air and battling police.
A gun battle broke out when gunmen blocked a main road and attacked a convoy going to meet the police chief.
Members of an armed affiliate of the mainstream Fatah party, which lost recent polls, are protesting over jobs.
There were at least five attempts by members of the al-Aqsa Martyrs Brigades to disrupt government activities on Monday - a day after the victorious Islamist group Hamas named its new cabinet.
The most serious was when about 30 militants charged the foreign and finance ministries and exchanged fire with security forces.
Two gunmen and two security officials were wounded - one of them hit by stray bullets in the legs as other employees ran for cover.
An Associated Press correspondent who was in the foreign ministry building reported that police stormed the building and searched room to room for the gunmen.
Three al-Aqsa members were eventually arrested, he reported.
Road block
Earlier, gunmen had briefly taken over Gaza's power plant and tried to seize control of a military hospital. No-one was injured.
But two officers and a gunman were hurt during the clash on the main road near the Erez crossing between Israel and the Gaza Strip.
A convoy of official vehicles had been going to pick up Palestinian police chief Alaa Hosni, who was travelling to Gaza from the West Bank.
About 30 gunmen had blocked the road to demand the authorities give them jobs in the Palestinian security services, reports say.
Palestinian Authority President Mahmoud Abbas was scheduled to use the road later on Monday to return to Ramallah. Erez is on the only direct route between the West Bank and Gaza Strip which crosses Israeli territory.
Gunmen also briefly shot at Gaza's main police station. Guards returned fire but there were no casualties.
BBC correspondent Alan Johnston says brief, violent protests like this have become quite common in Gaza and are a reflection of a chronic lack of law and order and how desperate some are becoming as poverty deepens.
In a separate development, reports said Israel would briefly reopen the Karni goods crossing between Israel and Gaza to allow food deliveries, following warnings of an impending humanitarian crisis.
A separate crossing at Kerem Shalom was also going to be allowed to open temporarily to allow trucks from Egypt to cross into Gaza, the reports quoting Israeli government officials added.