Gunmen loyal to Palestinian Authority President Mahmoud Abbas have set fire to the offices of the Hamas prime minister and parliament in Ramallah.
Palestinian gunmen also fired at the parliament building in Ramallah
Security personnel and militiamen fired shots then rampaged through the offices in protest at earlier Gaza clashes.
Hamas MP Khalil Rabei was briefly kidnapped, but later released.
Hamas and Mr Abbas's Fatah factions have been involved in a power struggle since the Palestinian elections in January, which were won by Hamas.
Earlier on Monday at least two people were killed and more than a dozen injured in Rafah in the Gaza Strip, amid escalating tension between the rival political groups.
The Ramallah rampage erupted hours after Hamas gunmen attacked a building belonging to the Fatah-dominated Preventive Security agency in Rafah.
Correspondents say security forces took to Ramallah's streets with gunmen from the Fatah offshoot the al-Aqsa Martyrs' Brigades.
Gunmen shot out the windows of the Palestinian parliament and stormed the cabinet offices, smashing furniture and computers.
The office was unoccupied as Ismail Haniya is based in the Gaza Strip.
It is not clear if there have been any casualties, but the buildings reportedly suffered heavy damage.
Militants tried to prevent fire engines from reaching the site to extinguish the flames.
"Every time they touch one of ours in Gaza, we will get 10 of theirs in the West Bank," a member of the security service said, quoted by the Associated Press news agency.
Tensions have worsened between the two sides since Mr Abbas called a referendum on a statehood plan which would implicitly recognise Israel, whose right to exist Hamas rejects.
At least 20 people, mostly militia members, have been killed in clashes between the two factions in the past two months.
Earlier on Monday a Hamas gunman was killed in a clash with security forces loyal to Fatah in Rafah.
The man was shot dead during a funeral for a fellow militant in Rafah. Each side blamed the other for firing first.
In addition to the clash at the funeral in Rafah, eyewitnesses say Hamas gunmen fired rocket-propelled grenades and anti-tank rockets at the security headquarters. One person was killed and more than a dozen wounded.