DIYARBAKIR, Turkey (Reuters) - Three Turkish soldiers were killed and 12 were wounded on Friday when three separate roadside bombs hit military vehicles in Turkey’s largely Kurdish southeast, security sources said.

There was no immediate claim of responsibility, but the sources said Kurdistan Workers’ Party (PKK) militants were suspected of having planted the bombs.

The bomb which killed the three soldiers was set on a road between the provinces of Diyarbakir and Mardin. The two others were in the provinces of Van and Hakkari and wounded 12 soldiers, two of them critically, the sources said.

Southeastern Turkey has witnessed numerous bombings since the PKK, which has waged a three-decade insurgency for Kurdish autonomy in the region, abandoned a ceasefire in 2015.

The PKK is considered a terrorist group by the United States and European Union, as well as by Turkey. More than 40,000 people, most of them Kurds, have died in the 32-year conflict.