A hard-line anti-migrant party on Wednesday threw its weight behind the opposition candidate who is running against President Recep Tayyip Erdogan in this weekend's runoff presidential race.

Umit Ozdag, the leader of the far-right Victory Party, announced his support for main opposition party leader Kemal Kilicdaroglu, who will be facing off against Erdogan on Sunday. He said he decided to back Kilicdaroglu over his promises to repatriate millions of migrants.

Ozdag's announcement came just days after Sinan Ogan, the third-placed contender in the first round of the presidential election on May 14, endorsed Erdogan in the upcoming runoff. Ogan was the joint candidate of an alliance of small conservative parties, led by Ozdag's Victory Party.

Erdogan received 49.5% of the votes in the first round of the presidential race — just short of the majority needed for an outright victory — compared to Kilicdaroglu's 44.9%.

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Erdogan's ruling party and its nationalist and Islamist allies also retained a majority in the 600-seat parliament — a development that increases Erdogan's chances of reelection because voters are likely to vote for him to avoid a splintered government, analysts say.

In an apparent attempt to woo nationalist voters in the runoff, Kilicdaroglu hardened his tone last week, vowing to send back refugees and ruling out any peace negotiations with Kurdish militants if he is elected.

Kilicdaroglu, 74, is the joint candidate of a six-party opposition alliance, which has pledged to reverse Turkey's authoritarian drift under Erdogan and return the country to a parliamentary democracy with increased checks and balances.

Turkey is home to the world's largest refugee community, including 3.7 million Syrians. Anti-migrant sentiment is running high in the country amid economic turmoil, including high inflation, and the issue of the repatriation of migrants has become a main campaign issue.