Palestinian security forces arrested 36 Hamas supporters, many of them professors and students, the Islamic militant group said Thursday, signalling a widening crackdown by Western-backed Palestinian President Mahmoud Abbas.

Palestinian police spokesman Adnan Damiri confirmed that arrests were made, but would not say how many persons are held.

The arrests come less than two weeks after a pair of deadly shootouts between security forces and Hamas militants in the West Bank town of Qalqiliya left nine people dead, including four police officers.

Abbas started going after Hamas two years ago when the militant group overran Gaza, leaving him only in control of the West Bank.

Since then, his forces have arrested hundreds of Hamas activists, shut down Hamas-affiliated institutions and tried to dry up the group's sources of funding. In parallel, Israel has also kept pursuing Hamas members, including gunmen, legislators and academics.

The Palestinian president is under pressure from Israel and the international community to show he can ensure security in the West Bank, a step considered a prerequisite for statehood.

Abbas' Palestinian critics say that under the guise of going after militants, the security forces have also detained political rivals. The latest sweep, which began Wednesday, included 17 students from a United Nations-run teachers' institute.

Damiri denied the allegations, saying all those arrested were tied to crimes involving handling weapons and money for Hamas or "incitement against the Palestinian Authority," which Abbas leads.

Damiri said the Palestinian Authority currently detains about 300 Hamas numbers. Hamas says the number is higher.