President Recep Tayyip Erdogan’s AK Party has challenged the results of the local elections in all districts of Istanbul and Ankara, party officials said on Tuesday. The AK Party is on track to lose control of what are Turkey’s two biggest cities, its commercial hub of Istanbul and the capital Ankara, in a surprise election setback that may complicate Erdogan’s plans to combat recession. In Istanbul, the mayoral candidate of the main opposition Republican People’s Party (CHP), Ekrem Imamoglu, and his AKP rival, ex-prime minister Binali Yildirim, both said on Monday Imamoglu was around 25,000 votes ahead. Istanbul has an estimated total population of 15 million. The AKP had previously said it would use its right to object to the results where there were voting irregularities, adding that the errors at the ballots had affected the outcome. On Tuesday, Bayram Senocak, the AKP’s Istanbul head said that objections had been submitted by the 3 pm (1200 GMT) deadline for appeals, and added that legal action would be taken against electoral officials who made the errors. “We have submitted all our appeals to the district electoral councils,” Senocak said, as he waved ballot records in which he said vote count irregularities could be seen. Some 319,578 votes in Istanbul that were declared void "can affect the result of the election," Senocak said. An AKP deputy chairman later said the difference between Imamoglu and Yildirim was down to 20,509 votes and would keep falling as a result of their appeals. He said the elections were “the biggest blemish in Turkish democratic history.” The CHP’s Istanbul head Canan Kaftancioglu said her party submitted objections in 22 districts, adding they expected to receive 4,960 more votes after the appeals were resolved. “They are trying to steal the will of the people as it was reflected in the ballots,” she told reporters in Istanbul. The CHP’s Imamoglu said on Tuesday he was saddened by the AKP failure to congratulate him after the election board count put him ahead. “I’m watching Mr. Binali Yildirim with regret. You were a minister of this nation, the parliament speaker and a prime minister,” Imamoglu said in Istanbul. “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 honor, so we can do our job,” he said. Imamoglu, who laid a wreath at the mausoleum of modern Turkey’s founder, Mustafa Kemal Ataturk, in Ankara, later went to CHP headquarters to meet Mansur Yavas, the opposition’s candidate in the capital. Speaking at the CHP building, Imamoglu said the elections marked a “moment of beginning” for Turkey. In Ankara, Yavas received 50.9 percent of votes, ahead of his AKP rival and former minister Mehmet Ozhaseki in Sunday’s local elections by nearly 4 percentage points. The AKP said it had also submitted objections to results across Ankara. Defeats in Ankara and Istanbul would be a significant setback for Erdogan, who has dominated Turkish politics for more than 16 years. He had campaigned relentlessly ahead of the vote, describing it as a “matter of survival” for the country.