Eight Turkish soldiers were killed on Wednesday in a bomb attack on their vehicle in the southeast blamed on the outlawed Kurdistan Workers’ Party (PKK), the army said.

The attack is the single most deadly strike to be blamed on the PKK since the government began waging a major “anti-terror” campaign against the Kurdish militants last month.

The soldiers were killed when a remote-controlled explosive device laid by militants on a road in the Silvan district of the province of Siirt was detonated, the official Anatolia news agency said.

The army confirmed the toll in a statement, blaming the “Separatist Terror Organisation”, its customary phrase for the PKK which it never refers to by name.

Seven soldiers were also wounded in the attack and military helicopters and ambulances were dispatched to the area, Anatolia said, adding that the clashes between the militants and soldiers were continuing.

Turkey has been on heightened alert since Ankara launched a two-pronged offensive to bomb Islamic State (IS) militants in Syria and PKK rebels in northern Iraq and southeastern Turkey following a series of deadly attacks.

So far, the operation has focused largely on the Kurdish rebels, who have responded by tearing up a 2013 ceasefire and waging a bloody campaign against the security forces.

At least four Turkish soldiers have also been killed in two days of clashes that erupted after Kurdish militants set up roadblocks on the highway between the Lice district of Diyarbakir and Bingol province in southeast Turkey, the army said Wednesday.

The latest deaths came as two suspected gunmen on Wednesday were reported to have opened fire on guards outside the Dolmabahce Palace in central Istanbul, with no casualties reported.