If the appeal is approved, fresh voting will take place on June 2, 60 days after the initial vote.

Turkish President Recep Tayyip Erdogan‘s Justice and Development Party (AK Party) has submitted an appeal for the annulment and rerun of a municipal election in Istanbul, the country’s largest city.

The move on Tuesday came more than two weeks after unofficial results showed the main opposition Republican People’s Party (CHP) narrowly win in Istanbul.

The city has been governed by the AK Party and its predecessors for 25 years.

Citing alleged irregularities, the AK Party had previously pushed for a recount of votes, and the process is still under way in one Istanbul district.

Ali Ihsan Yavuz, AK Party’s deputy chairman, submitted his party’s extraordinary appeal for the annulment and renewal of the elections to Turkey‘s High Election Board (YSK) with three suitcases full of documents.

“We have suspicions [about Istanbul’s elections] and we still were not able to resolve these doubts,” said Ali, adding that only the YSK could resolve this doubt.

If the appeal is approved, a fresh election will take place on the first Sunday 60 days after the initial vote, which will be on June 2. If rejected, the results will be finalised and the winner will receive his mandate to run the city.

“It is something of a gamble for the AK Party. If indeed, there is a rerun of the vote here,” Al Jazeera’s Neave Barker, reporting from Istanbul, said.

“Erdogan’s party will have to try and mobilise their voter base amass again to make sure that they are outright winners.”

CHP supporters have called for the mayoral mandate to be given to their candidate [Yasin Akgul/AFP]

After the March 31 vote, electoral authorities had said CHP’s Ekrem Imamoglu was ahead of AK Party’s Binali Yildirim by nearly 30,000 ballots. But that margin has narrowed to around 14,000 after a recount of void ballots over the last fortnight.

Repeated AK Party challenges have fuelled frustration among CHP supporters.

They spilled over into football stadiums over the weekend as fans chanted at top Istanbul derby matches for the mayoral mandate to be given to their candidate.

The political uncertainty has added to unease in financial markets. After the AK Party’s YSK move, the beleaguered lira weakened to 5.8250 against the US dollar, its lowest level since March 22, bringing its losses this year to nine percent.

The AK Party has already lost control of the capital, Ankara, as well as other key cities across the country.

Defeat in Istanbul, where Erdogan was mayor in the 1990s, would deal a bigger blow to the president.

“The Turkish economy has been hit by recession, inflation is at 20 percent, the value of the Turkish lira has plummeted by 30 percent, and worries about the handling of the economy may well have been reflected not only in Ankara but also in Istanbul, where the results are pending,” said Barker.