Turkey's main opposition party said on Wednesday it had filed complaints over suspected irregularities at thousands of ballot boxes in Sunday's landmark elections, in which President Tayyip Erdogan performed better than expected.

However, opposition party officials said the objections were unlikely to alter the result of the presidential vote, which is headed to a runoff on May 28 between Erdogan and challenger Kemal Kilicdaroglu.

Muharrem Erkek, a deputy chairman of the secularist Republican People's Party (CHP), said irregularities at each ballot box ranged from one single wrongly counted vote to hundreds of such votes.

He said the CHP had formally raised objections over 2,269 ballot boxes nationwide for the presidential election and 4,825 for the parliamentary vote that also took place on Sunday, though they represent a tiny proportion of the total number.

"We are following every single vote, even if it does not change the overall results," Erkek told reporters in Ankara.

Erdogan's ruling Islamist-rooted AK Party and its nationalist allies won a strong parliamentary majority, while in the presidential vote, Erdogan fell just shy of the 50% threshold needed to win outright.

Kilicdaroglu, the CHP chair, received 44.9% in what was seen as the biggest electoral challenge to Erdogan's 20-year rule. A third candidate, Sinan Ogan obtained 5.17%.

Erdogan, now in pole position, says only he can ensure stability in Turkey, a NATO member state, as it grapples with a cost-of-living crisis, soaring inflation and the impact of devastating earthquakes in February.

The opposition alliance that includes the CHP has urged young voters to turn out to support Kilicdaroglu in the runoff.

Mehmet Emin Ekmen, a deputy chairman of DEVA, one of six parties in the opposition alliance, told Reuters: "We do not have strong evidence to say irregularities can change the presidential race results or get another opposition candidate elected to the parliament".

"Since Erdogan officially started his election campaign yesterday, I believe the opposition alliance should also channel its energy into the runoff," he said.

Reuters