Four people have been killed in fighting in the West Bank city of Qalqilya.

The fighting began when Palestinian Authority police attempted to arrest a member of Hamas. In the subsequent gunfight, one policeman and three Hamas members were killed. On Sunday, six people died in the same city in a similar incident in the city.

Hamas and Palestinian Authority President Mahmoud Abbas’ Fatah movement have been enemies since 2007, when Hamas took power in the Gaza Strip. Fatah controls the West Bank.