Four construction workers have been killed and nine injured by a roadside bomb in the south-eastern Turkish province of Sirnak, officials say.
The provincial governor's office said the explosive device was believed to have been laid by the separatist rebel Kurdistan Workers' Party (PKK).
The PKK launched an armed struggle in 1984, calling for an independent Kurdish state within Turkey.
More than 40,000 people have been killed in the ensuing conflict.
Correspondents says PKK fighters have in the past frequently used roadside bombs and landmines to target Turkish soldiers in the region.