Ramallah - A Palestinian security officer was killed Thursday in clashes with armed gunmen in the northern West Bank city of Qalqilya, according to unconfirmed reports.

Witnesses said a Palestinian security force surrounded a building in the city, where similar clashes on Sunday led to six deaths, after receiving information that armed gunmen were inside, believed to be members of the armed wing of the Islamist movement Hamas.

Intermittent exchange of gunfire was reported in the area and witnesses said a hand grenade was thrown from the building at the security forces killing one.

The security forces have maintained an ongoing siege of the building calling on the armed men to surrender.(dpa)