Palestinian leader Mahmoud Abbas has ordered a crackdown on armed militants in Ramallah after gunmen opened fire at his West Bank headquarters.
The gunmen were thought to be loyalists under pressure to lay down their arms to foster peace moves with Israel.
About 15 fired in the air and rampaged through the streets, damaging restaurants and forcing shops to close.
Lawlessness plagues Palestinian areas after years of conflict which has devastated the Palestinian Authority.
"The Palestinian Authority has taken urgent steps to re-establish security, deal with the perpetrators and protect public property," a statement said.
It added that units had been deployed to "prevent any new aggression".
Mr Abbas was elected PA president in January on a pledge to restore law and order and reform the chaotic and corrupt security system created under the late leader Yasser Arafat.
Anger
Correspondents said the unidentified gunmen probably belonged to the militant al-Aqsa Martyrs Brigades, which is affiliated to the Fatah faction which Mr Abbas leads.
They fired volleys of bullets into the air in the courtyard of the Muqataa compound, near where Mr Arafat's is buried.
One report says they were furious at being ejected from the compound where they had been living for the last few months.
Israel is demanding that the Palestinian Authority disarm and dismantle all militant groups.
Elsewhere in the West Bank, a Palestinian security checkpoint was burned down by angry residents of the town of Tulkarm.
Residents were apparently reacting to the shooting of three people who had crashed through the checkpoint in their car.
Israel handed practical control of Tulkarm - and the quiet Jordan Valley town of Jericho - to the Palestinian Authority earlier in March.
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