Ankara: Four Turkish police officers were killed on Monday in a roadside bomb attack in the southeast blamed on Kurdish militants, local media reported.

The mine explosion took place in the Silopi district of Sirnak province bordering Iraq and Syria, the private Dogan news agency said. It came after Turkey’s megacity Istanbul was rocked by twin attacks, one on a police station and the other on the US consulate.

Meanwhile, in a separate incident, one Turkish soldier was killed when Kurdish militants attacked a military helicopter with rocket launchers as it was transporting personnel in Sirnak’s Beytussebap district, Dogan said.

The attack prompted an air operation by the Turkish military with Cobra helicopters bombing the area.

The violence between Turkey’s security forces and the outlawed Kurdistan Workers’ Party (PKK) has intensified since last month following a suicide bombing in a town on the Syrian border blamed on the Islamic State.

Since then, Ankara has launched a two-pronged offensive to bomb IS militants in Syria and PKK rebels in northern Iraq and southeast Turkey — who are bitter enemies themselves.

So far, the operation has focused largely on Kurdish rebels.

The PKK, designated as a terrorist organisation by Turkey, the EU and the United States, took up arms for self-rule in the southeast in 1984, and the conflict has since claimed tens of thousands of lives.