President Recep Tayyip Erdogan has secured the endorsement of Turkey’s third-placed presidential election candidate, Sinan Ogan, ahead of Sunday's runoff vote.
Ogan's 5.2% of vote prevented Erdogan from winning outright for the first time in 20 years last week.
On Friday, Ogan, called by some analysts a potential “kingmaker," said in a news conference in Ankara that he will back the incumbent president.
Erdogan received 49.52% of votes in the first round of voting on May 14. He fell just short of the majority needed to secure an outright victory.
Erdogan's challenger, Kemal Kilicdaroglu, the candidate of a six-party opposition alliance, won 44.88 percent.
"I invite voters who backed us in the first round to support Mr. Erdogan in the second round," Ogan told reporters.
Ogan met the Turkish president on Friday and also held separate negotiations with allies of Kilicdaroglu.
“The National Alliance has failed to convince us,” he said, speaking of the main opposition group in Turkey, led by Kilicdaroglu.
Kilicdaroglu sounded defiant in a tweet posted moments after Ogan's announcement, accusing unnamed forces of "selling out this beautiful country" and he signaled his intention to continue pursuing the nationalist voters.
"We are coming to save this country from terrorism and refugees," he wrote. "This is a referendum. No one can fool anyone anymore.”
Kilicdaroglu pledged to send "all the refugees home" when he comes to power and accused Erdogan of failing to "protect the borders and honor of our country."