A Hamas member of the Palestinian parliament was briefly kidnapped by gunmen, and later Mahmoud Abbas, the president, ordered security forces to take control of the streets in the wake of the fighting between rival gunmen from Fatah and Hamas.
Fatah gunmen said they seized Halil Rabai after attacking Hamas offices in Ramallah. The gunmen said they destroyed the office and set it on fire.
Rabai was later freed by the Fatah gunmen.
Fatah security forces also attacked the parliament and cabinet buildings in the Gaza Strip.
One cabinet building was set on fire and the windows of the parliament building were shot out. Furniture was smashed, computers destroyed and documents torn up as Fatah gunmen went on the rampage against the Hamas-led government.
Flames spread quickly through the cabinet building, causing extensive damage. When a fire engine arrived at the scene, one gunman lay down in front of it and prevented it from reaching the blaze.
"Every time they touch one of ours in Gaza, we will get 10 of theirs in the West Bank," said a member of the Preventive Security force, which is loyal to Abbas's Fatah movement.
Dozens of gunmen from the al-Aqsa Martyrs' Brigades, a pro-Fatah militia, joined the security men.
Abbas put security services on a maximum state of alert after the violence, a security official told AFP.
The violence followed an attack by Hamas gunmen on a Preventive Security building in Rafah. A shootout began when Hamas gunmen, attending the funeral of a colleague killed in clashes with Fatah, opened fire on the offices. The attack set off a day of clashes which left two people dead and at least 14 wounded.
Palestinian security forces are
largely loyal to Abbas and Fatah
A senior Hamas official was also kidnapped for a short time by masked gunmen in the southern Gaza Strip, Palestinian security sources and witnesses said.
Salah al-Rantissi, who practises as a doctor in the southern town of Khan Yunus, was taken from his surgery at gunpoint by masked men.
Sami Abu Zuhri, a Hamas spokesman, accused members of the Palestinian Preventive Security service of being behind the kidnapping.
Al-Rantissi is the brother of Abd al-Aziz al-Rantissi, the former leader of Hamas who was assassinated by the Israeli military in 2004.
Al-Rantissi was freed less than two hours later, after appeals from Osama al-Farra, the governor of Khan Yunus, and local leaders in the Fatah-linked al-Aqsa Martyrs' Brigades, security sources said.