ANKARA: Suspected Kurdish militants hurled a hand-made explosive device at a middle school in the mainly Kurdish city of Diyarbakir on Friday, injuring five students, officials said.

The attack targeted the Celebi Eser middle school in Diyarbakir's Baglar district on the last day of school when students receive report cards before a winter break, the regional education official Adnan Hurata told the state-run Anadolu Agency.

Turkey's security forces are fighting militants linked to the Kurdistan Workers' Party, or PKK, in Diyarbakir's historic Sur district. Authorities are enforcing a 24-hour curfew in Sur as the security forces press ahead with large-scale operations to rout out the militants. A Turkish human rights group says more than 160 civilians have been killed since August, caught up in the conflict in the rural areas.

All five students were hospitalized but none of them is in serious condition, Hurata said.

The Kurdish rebel group, which wants autonomy for Kurds in southeastern Turkey, has targeted schools in the past because it oppose the Turkish education system, which it says aims to assimilate Kurds.

Fighting between the PKK and the security forces reignited in July, shattering a two-yea-old peace process that aiming to end the three-decade conflict that has killed tens of thousands of people.