Third-party candidate Muharrem Ince on Thursday withdrew from Turkey's tight presidential election in a shock move that raised the chances of an opposition first-round victory.

The 59-year-old announced his decision after being targeted by an online smear campaign that included doctored images of him meeting women and riding around in fancy cars.

The secular nationalist picked up 30.6 percent of the vote when he challenged President Recep Tayyip Erdogan in 2018 presidential polls.

He then quit the main opposition party and launched his own movement that began to pull votes away from secular leader Kemal Kilicdaroglu -- the joint candidate of the anti-Erdogan bloc.

"I'm withdrawing my candidacy," Ince told reporters ahead of Sunday's vote.

"I am doing this for my country."

Ince came under ferocious criticism from the opposition for entering the campaign.

Most saw him as a spoiler candidate who could only help Erdogan secure a third decade of rule.

Ince countered that he offered voters a more vibrant alternative to the 74-year-old Kilicdaroglu -- a bookish former civil servant, who lost a string of national elections against Erdogan.

- Tight race -

The last opinion polls showed Kilicdaroglu leading Erdogan by a few percentage points and falling just short of breaking the 50-percent threshold needed for a first-round win.

Ince's popularity has been ebbing away after touching nearly 15 percent.

The latest surveys showed him picking up between two and four percent of the vote.

But that might be enough to put Kilicdaroglu over the top.

The Metropoll survey showed 30.5 percent of Ince's support falling to Kilicdaroglu and 23.4 percent going to Erdogan.

Ince notably did not endorse any candidate after dropping out.

His name will also still appear on the presidential ballot.

A fourth minor candidate -- nationalist Sinan Ogan -- is believed to be mostly drawing votes away from Erdogan.

"Another crazy day in Turkish politics," emerging markets economist Timothy Ash remarked.

"Ince withdraws, with the assumption that most of his votes now go to Kilicdaroglu, making it possible/more likely of a (Kilicdaroglu) first round win."

Kilicdaroglu has been appealing for days for Ince to formally back his candidacy.

Erdogan, meanwhile, has been staging daily rallies at which he announced incentives and bonuses to voters aimed at spurring support.

The 69-year-old Turkish leader pledged on Thursday to double the size of a previously promised wage hike for public workers.

zak/kjm