Istanbul will hold a do-over of its mayoral election on Sunday, after authorities threw out the results of a March victory for opponents of Turkey’s strongman President Recep Tayyip Erdogan.

The race pits the winner of the first vote, political newcomer Ekrem Imamoglu, 49, against pro-government candidate Binali Yildirim, 63.

Imamoglu was mayor for 15 days before his victory was annulled. He was booted out of office in May.

Erdogan looked to a jailed Kurdish leader to urge Kurds to stay home, depriving Imamoglu of votes, according to Voice of America.

Imprisoned Kurdistan Workers’ Party head Abdullah Ocalan, in a handwritten letter, called on Kurds to remain “neutral” in the balloting.