A look at candidates running in Turkey's presidential race

Turkey is holding snap presidential and parliamentary elections on Sunday — more than a year earlier than scheduled. The elections will usher in a new system of governance giving the president expanded powers that was narrowly approved in a referendum last year. ABC News wrote an article about six candidates who are running for the presidency.

RECEP TAYYIP ERDOGAN

In power since 2003 as prime minister and president, Erdogan, 64, is vying for a new five-year term in office under a new system that grants the president vast powers. A favorite to win, most opinion polls show him ahead of his rivals. However, a first-round victory on Sunday is not certain and a second round runoff vote could take place on July 8.

Once a reformist, Erdogan has become a highly polarizing figure and taken an authoritarian turn, curtailing free speech and jailing tens of thousands. He presided over an economic boom, championed large infrastructure projects and remains popular among conservative and pious supporters. He promises to make Turkey one of the major world economies by 2023, when the Turkey Republic celebrates its centenary. Erdogan is backed by both his ruling religious-conservative Justice and Development Party, or AKP, and two nationalist parties.

MUHARREM INCE

Ince, a 54-year old former physics teacher and school principal, is backed by Turkey's main opposition, the pro-secular Republican People's Party. Quick-witted and pugnacious, his election rallies have drawn large crowds and opinion polls indicate that his popularity has surged. Ince promises to change the constitution and return Turkey to a parliamentary system with distinct separation of powers. He has also vowed to end the state of emergency that Erdogan's government declared after a failed military coup in 2026 which allows the government to rule by decrees, often by-passing parliament. Ince wants improved relations with the European Union, and to reform Turkey's poor education system. The son of a farmer with humble origins, he has sought to appeal to Turkey's conservative and religious sections and to Kurds.

MERAL AKSENER

Turkey's only female presidential candidate, Aksener is a former interior minister who served between 1996 and 1997 and a popular former deputy parliament speaker. The 61-year-old split from Turkey's nationalist party following a spat with its leader over his support to Erdogan in a referendum to increase presidential powers. Last year she established the Good Party, made up of former nationalists and center-right figures. Like Ince, Aksener is a strong critic of Erdogan and has vowed a swift return to a parliamentary system with stronger checks and balances. Aksener and Ince have said they would support each other against Erdogan in a runoff second-round presidential vote.

SELAHATTIN DEMIRTAS

The charismatic 45-year-old former co-chairman of the pro-Kurdish Peoples' Democratic Party, or HDP, has one distinct disadvantage over his rivals: he is in jail. Arrested in November 2016, Demirtas has run a campaign from his high-security prison in Edirne, northwest Turkey, while he fights terror-related charges for alleged links to outlawed Kurdish rebels. The politician, a former human rights lawyer, can run for office because he has yet to be convicted. Over the years, Demirtas broadened his party's appeal beyond Turkey's mostly Kurdish-populated southeast region, winning the support of left-leaning and liberal voters. His party, however, is criticized for not sufficiently distancing itself from Kurdish rebels.

TEMEL KARAMOLLAOGLU

The 77-year old politician is the leader of the small Islamic-oriented Felicity Party, of which Erdogan's ruling AKP party is an offshoot. Strongly critical of Erdogan's policies, Karamollaoglu has aligned his party with those of Aksener and Ince, and is likely to back them in the event of a runoff presidential vote against Erdogan. The British-educated engineer is a former State Planning Organization official and former mayor of the conservative city of Sivas.

DOGU PERINCEK

The chairman of the nationalist, far-left Patriotic Party, the 75-year old politician was a leading figure in Turkey's leftist movement in the '70s and '80s. He spent time in prison following the country's 1980 military coup and then again in 2007, accused of plotting against Erdogan's government in a trial that was later widely accepted to be bogus. An anti-imperialist, he opposes NATO and wants the ouster of U.S. jets from the Incirlik air base in southern Turkey. He advocates close ties with China and Russia. In 2007, he was sentenced by a Swiss court for denying that the killings of Armenians in the waning years of the Ottoman Empire constituted genocide. However, in 2015 the European Court of Human Rights defended his right to free speech.