Voters in Turkey will go to the polls on Sunday to determine whether long-ruling President Recep Tayyip Erdogan can remain in power.

The race is being seen as a head-on clash between Erdogan, who is seeking reelection, and Kemal Kilicdaroglu, the leader of the largest opposition party. Kilicdaroglu is the joint candidate of six opposition parties.

Erdogan has 20 years of experience as the country's prime minister and president. Last year, he helped broker a deal that allowed Ukrainian farm products to be exported via the Black Sea. The exports had been blocked, due to Russia's invasion of Ukraine.

Kilicdaroglu has been highlighting the plunge of the lira, Turkey's currency, and an increase in prices under the current administration.

He has criticized the government for delays in its initial responses to the major quakes that struck southern Turkey in February. He has also accused the government of allowing buildings that did not meet quake-resistance standards to be constructed.

The opposition leader has vowed to improve Turkey's relations with Western nations, as they have soured since Erdogan assumed office.

Some of the latest opinion polls show Kilicdaroglu leading Erdogan by a small margin. Many observers believe the withdrawal of another opposition candidate from the race, just three days before election day, is helping Kilicdaroglu.

However, some analysts believe the polls underestimate Erdogan's support, as the surveys were mainly conducted in urban areas.

Votes will be counted on the same day. But if none of the presidential candidates wins a majority, a run-off election will be held between the top two contenders on May 28.