Turkish lawmakers have been voting in the first round of a presidential election, but their number fell short of a 367-member threshold and the opposition confirmed it would contest the vote in court.
Foreign Minister Abdullah Gul is seeking to become president in an election which has exposed deep divisions between Turkey’s Islamist-rooted government and its secular elite.
The ruling AK Party now faces the biggest crisis of its near five-year rule.
If the court upholds the opposition appeal, Prime Minister Tayyip Erdogan will have to call a snap general election.
If Gul gets a two-thirds majority in round two he will be automatically elected.
But in the third round, on May 9, he would only need a straight majority, which he is almost certain to win.