Turkish President Recep Tayyip Erdogan‘s party has challenged the results of the local elections in the country’s two biggest cities, where preliminary results show narrow victories for the opposition candidates.

Nationwide, the Justice and Development Party (AK Party) and its coalition partner won more than 50 percent of votes in Sunday’s election, but the ruling party lost the capital, Ankara, and its commercial hub, Istanbul.

Bayram Senocak, the AK Party’s top official in Istanbul, said on Tuesday he has submitted objections to results in all 39 of the city’s districts, seeking a recount to fix alleged irregularities and a reassessment of invalid votes.

The move came a day after electoral authorities announced Ekrem Imamoglu, the mayoral candidate of the main opposition Republican People’s Party (CHP) in Istanbul, was ahead of his AK Party rival – ex-Prime Minister Binali Yildirim – by about 28,000 votes.

Speaking to reporters, Senocak said: “As of 15:00 [hours] today, we have submitted all our appeals to the district electoral councils.”

The AK Party had found an “excessive” difference between votes cast at ballot stations for their candidate and the data sent to electoral authorities, he said.

Waving ballot records, in which he said the vote count irregularities could be seen, Senocak added: “Whichever officials did this and for whatever reason, we will closely follow the necessary legal steps.”

In Ankara, Hakan Han Ozcan, AK Party’s chairman in the capital, told reporters they were also filing an appeal in 25 districts of the city.

Mansur Yavas, the CHP’s newly elected mayor in Ankara, received 50.9 percent of votes in Sunday’s vote, defeating his AK Party rival and former minister Mehmet Ozhaseki by nearly four percentage points.

The electoral board has two days to decide whether the claims of irregularities have merit.

‘Shame’

Meanwhile, Imamoglu, CHP’s mayoral candidate for Istanbul, said he was saddened by the AK Party’s failure to congratulate him after the election board count put him ahead.

Ekrem Imamoglu, flanked by his family members and supporters, visits Anitkabir, the mausoleum of modern Turkey’s founder Mustafa Kemal Ataturk, in Ankara [Umit Bektas/Reuters]

“I’m watching Mr Binali Yildirim with regret. You were a minister of this nation, the parliament speaker and a prime minister,” Imamoglu said on Tuesday at Istanbul’s Ataturk Airport before travelling to Ankara.

“What could be more noble than congratulating?”

“The world is watching us with shame right now. We are ready to manage the big city of Istanbul. Let go and congratulate us with honour, so we can do our job,” he said.

Imamoglu later laid a wreath at the mausoleum of modern Turkey’s founder, Mustafa Kemal Ataturk, in Ankara.

Large crowds gathered to greet him there, chanting “Mayor Ekrem”.

Defeats in Ankara and Istanbul come as a major setback for Erdogan, who has dominated Turkish politics for more than 16 years.

A former mayor of Istanbul, Erdogan had campaigned relentlessly before the vote, describing it as a “matter of survival” for the country.

The president’s political success has rested on years of stellar economic growth in Turkey, but a recession that has brought surging inflation and unemployment and a plunging lira currency have affected his popularity.