Three Turkish policemen were killed by Kurdish militants on Sunday in two separate attacks in Turkey’s southeast.

Three Turkish policemen were killed by Kurdish militants on Sunday in two separate attacks in Turkey's southeast, security sources said, as weeks of violence showed no sign of abating.

Two officers were killed and five wounded on a highway outside the southeastern city of Sirnak in a car bomb attack carried out by the Kurdistan Workers Party (PKK), the sources told AFP.

Security forces on attack helicopters then pursued the militants suspected of carrying out the attack, killing two, the sources said.

Meanwhile, one policeman was killed and one more wounded in a rocket attack carried out by the PKK in the Silvan district of the southeastern region of Diyarbakir.

Since late July, Ankara has used air power and ground forces in a self-declared "anti-terror" operation to try to cripple the PKK in its strongholds in southeastern Turkey and northern Iraq.

But the group has hit back, killing dozens of Turkish police and soldiers in almost daily attacks.

The security forces had over the last week carried out a massive military operation against suspected PKK militants in the southeastern town of Cizre, lifting a curfew on Saturday after nine days.

The authorities on Sunday imposed a curfew in several districts of Silvan after the deadly attack on police, informing citizens of the measure through loudspeakers on mosques, Turkish media said.

A curfew meanwhile was also imposed in parts of the central Sur district of Diyarbakir city. It was not immediately clear how long the measures would last.