Security forces loyal to Palestinian President Mahmoud Abbas's Fatah faction have arrested more than 50 rival Hamas activists in the occupied West Bank.
Among those arrested by Mr. Abbas's forces Monday in the city of Nablus were several prominent local leaders and university professors. Authorities have not immediately given a reason for the arrests.
Tensions are running high between the rival Palestinian factions since a bombing in the Gaza Strip last Friday killed five Hamas members and a young girl.
Hamas accused Fatah of carrying out the attack, and has detained at least 160 Fatah supporters in Gaza.
Fatah has denied involvement, blaming the blast on Hamas infighting.
The two Palestinian factions have been at odds since Hamas routed Fatah forces in a civil war last year and seized control of Gaza.
Some information for this report was provided by AFP and Reuters.