Istanbul votes once again in key mayoral election re-run
Some 10 million people headed to the polls on Sunday to elect Istanbul's mayor, for a second time, in a repeated election that has posed difficult questions for Turkey's ruling party.
Polling stations opened at 8am local time (05:00 GMT) and closed at 5pm. Results are expected to emerge around 7pm.
Ekrem Imamoglu held the mayorship of Turkey's largest city for just 15 days following a vote in March, before the Supreme Election Board controversially annulled the result, citing unlawful staffing of polling stations.
With Imamoglu, the opposition Republican People's Party (CHP) candidate, winning that poll by just 13,000 votes, the ruling Justice and Development Party (AKP) has attempted to seize the opportunity and hold the key office.
However, despite a change in tack by the AKP's campaign, attempting to focus more on the strengths of its candidate, former prime minister Binali Yildrim, recent polls have show Imamoglu pulling ahead by up to nine percentage points.
Losing Istanbul to the opposition would come as a harsh blow to President Recep Tayyip Erdogan, who served as the city's mayor in the 1990s and has famously said "whoever wins Istanbul wins Turkey".
Erdogan and his AKP have in recent years cemented their power and dominance in the country through a series of national votes.
However, local elections on 31 March provided a number of upsets for the ruling party, which lost control of several key cities, including the capital, Ankara.
Turkey's ailing economy has been cited as one of several reasons behind the voters' rebuke of the AKP, and it is among a number of challenges Erdogan faces that include a diplomatic crisis with Nato ally the United States.
In contrast to Yildrim's first campaign, Erdogan has largely avoided intervening in this election, though last week the president's gloves came off, with the president lashing out at Imamoglu and implying the CHP candidate had links to the plotters of Turkey's 2016 coup attempt.
The AKP has used other, more unconventional methods of attracting voters, such as an attempt to woo Istanbul's Kurds, who make up about 15 percent of the city's population.
In the run-up to Sunday's vote, Yildrim has visited the Kurdish-majority city of Diyarbakir and described parts of Turkey as "Kurdistan".
Then on Friday, the campaign took a strange turn when jailed Kurdish militant leader Abdullah Ocalan called for supporters of the pro-Kurdish HDP party to remain neutral.
The HDP, which had previously thrown its weight behind Imamoglu, responded by claiming Ocalan's statement was an AKP attempt to divide the Kurds in a "desperate" move.
The pro-Kurdish party decided in January not to field a candidate in Istanbul's election.
It has been more explicit in its support of Imamoglu this time around in an attempt to seal his win by mobilising the estimated one million HDP voters in the city.
The HDP estimates some 20 percent of its supporters stayed at home in the March election, and turning out sluggish voters has become a key aim for both the AKP and CHP.
The AKP has also attempted attract votes from the Islamist-leaning Felicity Party, whose candidate won 103,000 votes last time around.