Muhammet Fatih Safiturk, the governor of Mardin's Derik district, died early on Friday from wounds sustained in a PKK terror attack on his office in the southeastern Mardin province a day earlier.
He had recently been appointed as the district's mayor after the previous mayor was detained to face charges of having links with PKK.
The ex-mayor was detained along with a number of other members from the Peoples' Democratic Party (HDP), including its co-leaders. They had refused to testify in court after being summoned.
Safiturk, the father of two children, succumbed to his wounds in the Ersin Arslan State Hospital in the nearby Gaziantep province, Gaziantep Governor Ali Yerlikaya said.
Three people, including Safiturk, were wounded in Thursday's attack.
After the attack, security forces apprehended 20 people in the district, said a security source who asked not to be named due to restrictions on speaking to the media.
After receiving treatment at the Dicle University Hospital in the neighbouring Diyarbakir province, Safiturk was later transferred to Gaziantep by helicopter.
The PKK – listed as a terrorist organisation by Turkey, the US, and the EU – resumed its decades-old armed campaign in July 2015 after unilaterally ending a two-year cease fire with the Turkish state.
Since then, the PKK have killed nearly 800 members of Turkey's security forces as well as over 300 civilians, including women and children.
More than 10,000 PKK terrorists have also been killed or apprehended in army operations.