Turkey yesterday voted in a general election which will determine whether the ruling party can change the constitution.

President Recep Tayyip Erdogan, who first came to power as prime minister in 2003, is seeking a big enough majority to turn Turkey into a presidential republic.

However his hopes may be scuppered if the pro-Kurdish HDP crosses the 10% threshold and enters parliament.

Polls across Turkey's 81 provinces opened at 08:00 local time and closed at 17:00. First results are expected late yesterday.

If the left-wing HDP succeeds in winning seats in parliament for the first time, it would reduce the number of seats won by Erdogan's AKP, thwarting its plans to change the constitution and transfer the prime minister's executive powers to the president.

A strong showing from the main opposition Republican People's Party (CHP) and the third-placed Nationalist Movement Party (MHP) could even force the AKP into a coalition, correspondents say.

Kemal Kilicdaroglu, chairman of the CHP echoed Dermirtas and called the campaign period "unequal". He promised however to "continue to work with a sense of responsibility".

Turkey's current Prime Minister Ahmet Davutoglu shied away from accusations of unfairness telling reporters: "Whatever [the people's] will, it is a will that must be respected by everyone.''

The BBC's Mark Lowen in Istanbul says yesterday's election is the biggest electoral challenge for the AKP since it came to power 13 years ago.