Voting is under way in Turkey elections as President Recep Tayyip Erdogan faces the biggest political challenge of his two-decade rule. Voters will elect a president for a term of five years. It is estimated that a total of 64 million voters will cast their votes in the 14 May elections, 60.9 million in Turkey and 3.2 million abroad.

Ahmet Yener, head of the Supreme Election Council, says voting continues in Turkey with no issues reported.

Years of economic crisis have eroded Erdogan's support. Many in the provinces affected by the earthquake, which killed more than 50,000 people, have expressed anger over the slow initial government response but there is little evidence that the issue has changed how people will vote.

A candidate must win over 50% of the vote on Sunday night in order to be elected. Otherwise, Turkey will head to a run-off on May 28.

Opinion polls give Erdogan's main challenger, Kemal Kilicdaroglu, who heads an alliance of six opposition parties, a slight lead.

Voters will also elect a new parliament, likely a tight race between the People's Alliance comprising Erdogan's conservative Islamist-rooted AK Party (AKP) and the nationalist MHP and others, and Kilicdaroglu's Nation Alliance formed of six opposition parties, including his secularist Republican People's Party (CHP), established by Turkey's founder Mustafa Kemal Ataturk.

Polls opened at 8 a.m. (0500 GMT) and will close at 5 p.m. (1400 GMT). Under Turkish law, the reporting of any results is banned until 9 p.m. By late on Sunday there could be a good indication of whether there will be a runoff vote for the presidency.