The crackdown is a sign of the failure of a nearly year-old unity deal between Hamas, which controls the Gaza Strip, and the rival Fatah which dominates the PA.
Under last April's unity deal, Hamas was to relinquish control of the Gaza Strip, paving the way for Palestinian general elections by the end of 2014.
The deal stalled during a July-August war in Gaza between Hamas and Israel, and because of disputes over wages and control of the enclave.