Fatah gunmen have stormed the Hamas-controlled Palestinian parliament building in Ramallah in the West Bank.
The gunmen scuffled with officials after trying to fly a flag inside
The gunmen reportedly tried to seize the Palestinian Legislative Council's second deputy speaker, Hassan Khuraishah, but staff intervened.
Mr Khuraishah told the BBC he had been beaten up as he tried to prevent Fatah gunmen from raising their flag.
The clashes came after Fatah was ousted from Gaza by Hamas, ending a week of clashes which left more than 100 dead.
The leader of Fatah, President Mahmoud Abbas, is due to swear in an interim Prime Minister, Salam Fayyad, to lead an emergency government after his predecessor was dismissed.
Aides to Mr Abbas say the government will be sworn in by Sunday.
The new government would receive the backing of Washington, the US consul-general in Jerusalem, Jacob Walles, said after a meeting with Mr Abbas. There has been speculation that the ban on direct aid could be lifted.
Dismissed Prime Minister Ismail Haniya, a Hamas leader, says his sacking is illegal, but has called for people to show self-restraint and ordered police to ensure the rule of law.
The Arab League has condemned the latest infighting in Gaza as "criminal" and pledged fresh support for Mr Abbas.
In a show of strength, supporters of Mr Abbas's Fatah movement paraded around Ramallah and fired weapons into the air.
They chanted "Hamas out" outside the parliament and climbed onto the building's roof to plant Fatah and Palestinian flags.
Later, they scuffled with officials after forcing their way into the office of one of the PLC's two deputy speakers and accusing him of being a Hamas supporter.
Mr Khuraishah, an independent, had been trying to stop members of a Fatah-linked militant group, the al-Aqsa Martyrs' Brigades, hanging a flag inside the building.
Other Fatah supporters ransacked the ministry of education, led by Hamas member Nasser Shair, although no-one was harmed in the attack.
Almost all Hamas politicians and prominent supporters in Ramallah have either fled or gone into hiding.
Fatah supporters also took over the Hamas-controlled legislative council in Nablus.
Gaza was reported to be relatively calm on Saturday, compared with recent days.
Hamas said the bodies of seven of its supporters had been found in a compound in Gaza City which had been used by pro-Fatah security forces.
The Islamist group said they had been kidnapped before being shot dead.
In Gaza City, Hamas members "sabotaged" the house of the late Palestinian president, Yasser Arafat, and took his personal belongings, the Wafa news agency reported.
The BBC's Aleem Maqbool in Ramallah says the political words may have become more conciliatory, but the actions on the ground have not.
President Abbas dismissed Ismail Haniya's three-month-old unity government on Thursday and declared a state of emergency.
Born in 1952 near West Bank city of Tulkarm
Holds a PhD in economics from the University of Texas
Worked at the World Bank in Washington from 1987-1995
IMF representative to Palestine until 2001
Finance minister under the Fatah-controlled administration from 2002-2005
Credited with cracking down on official corruption
He said he would rule by presidential decree until the conditions were right for early elections.
His nominee to replace Mr Haniya, Mr Fayyad, is a former World Bank economist, whose impending appointment Israel has welcomed.
Western nations have boycotted Hamas, considered a terrorist organisation by the US and EU, since it won elections in January 2006.
The US government says Mr Fayyad's administration will have its full support.
"I think... there won't be any obstacles, economically and politically, in terms of re-engaging with this [emergency] government. Yes, they will have full support," Consul-General Walles told Reuters news agency on Saturday.