For the first time in Turkey's history, the president will be elected by a popular vote on Sunday, in line with a constitutional amendment adopted in 2007.

Erdogan is looking to extend his more than 10 years in power in the culturally divided nation, with his main opponent Ekmeleddin Ihsanoglu, a conservative academic and diplomat who used to lead the Organization of Islamic Cooperation, hoping to score a surprise victory.

Ihsanoglu is supported by the left-leaning secularist Republican People's Party (CHP) and Nationalist Movement Party (MHP), the two largest opposition parties in the country, in addition to three smaller ones.

However, Ihsanoglu is a largely unknown figure among the Turkish public.

Selahattin Demirtas, a senior figure among Turkey's Kurdish minority, is the third presidential candidate. He is supported by the People's Democracy Party (HDP), a pro-minority rights party supported primarily by Kurdish Turks.

A survey conducted by Turkish pollster A&G put Erdogan at 55.1 percent, with Ihsanoglu predicted to gain 33 percent and Selahattin Demirtas 11.6 percent of the votes.

The presidential vote takes place just three months after Erdogan's ruling conservative Justice and Development Party's (AK Party) scored a landslide win in local elections.

The local elections were held in a tense political climate amid new internet controls, frequent anti-government protests and allegations of corruption surrounding Erdogan's government.

During his campaign, Erdogan has talked about infrastructure projects, foreign policy actions, economic reforms, and a new constitution featuring a presidential system, promising a more active presidency, a position which is highly symbolic in Turkish politics.

Conversely, Ihsanoglu has stressed "unity" and "neutrality", drawing a more traditional and passive picture for his potential presidency.

Unless a candidate receives more than 50 percent support in the first round, a runoff vote will be held on August 24 between the top two candidates.

NTJ/HH