The incident in the town of Qalqilya was another sign of growing lawlessness and frustration at the lack of economic opportunities in the Palestinian territories.
"We belong to Fatah. We ask you to leave your offices. The offices will be closed until our demands for employment are met. Our protest is peaceful so far," one of the Fatah members told the employees, who complied immediately.
The Fatah men then closed the offices with chains and locks and departed, leaving several members of the group behind to guard the building. Police did not intervene.
Abbas was elected in January to replace the late Yasser Arafat.
He promised during the presidential campaign to boost employment and recruit into Palestinian Authority institutions
resistance fighters who have confronted Israeli forces during a four-and-a-half year uprising. Promised jobs are yet to materialise.