ANKARA, Turkey (AP) — An improvised explosive device went off on a road in southeast Turkey on Wednesday, killing five forestry workers traveling to work, officials said.

The regional governor’s office blamed the early morning explosion near the town of Kulp, in the mainly-Kurdish populated Diyarbakir province, on Kurdish rebels, who have carried out similar attacks in the past.

There was no immediate claim of responsibility.

The Kurdistan Workers’ Party, or PKK, has waged a more than three-decade old insurgency in Turkey’s mostly Kurdish southeast region. The conflict has killed tens of thousands of people since it started in 1984.

The group is considered a terror organization by Turkey, the United States and the European Union.

The Diyarbakir governor’s office said Turkey’s military has launched an operation to catch the perpetrators of the attack.

Four villagers were killed last year in a similar attack on a road in Kulp, which was also blamed on the PKK.

Last week, an explosion in eastern Turkey, believed to be the work of the PKK, damaged a natural gas pipeline and halted gas flows from Iran.