The 55-year-old was among several Kurdish activists who entered the Turkish parliament in 1991, including human rights award winner Leyla Zana. They lost their seats three years later for supporting armed Kurdish rebels fighting the government.

Dogan, Zana and two others spent 10 years in jail for collaborating with the rebels before being released in June 2004.

Dogan had put forward his candidacy to run again in general elections on July 22, but electoral authorities said he was no longer eligible because of his conviction.

He suffered cardiac arrest while making a speech at a festival in the eastern town of Dogubeyazit on Sunday.