Security sources, requesting not to be named, said the blast took place in Midyat district of the province, about 1,100 kilometers (683 miles) east of the capital, Ankara, late on Wednesday as PKK militants detonated an explosives-laden car outside the Anitli Gendarmerie Command Headquarters, presstv.ir. reported.
Security forces immediately rushed to the scene and launched an investigation into the act of violence.
A shaky ceasefire between the PKK and the Turkish government collapsed in July 2015, and attacks on Turkish security forces have soared ever since.
Ankara has been engaged in a large-scale campaign against the PKK in its southern border region in the past few months. The Turkish military has also been conducting offensives against PKK positions in northern Iraq and Syria.
The operations began in the wake of a deadly July 2015 bombing in the southern Turkish town of Suruc. More than 30 people died in the attack, which the Turkish government blamed on the Daesh Takfiri terrorist group.
After the bombing, the PKK militants, who accuse Ankara of supporting Daesh, engaged in a series of supposed reprisal attacks against Turkish police and security forces, prompting the Turkish military operations.