Turkey's top electoral body ordered Monday on the basis of irregularities a renewal of the Istanbul local elections won by the opposition, a move that could escalate political tensions in the country.
After more than five hours of discussion, members of the Supreme Election Council (YSK) decided on a majority of seven to four to re-hold the elections for June 23, state-run Anadolu Agency reported.
The main opposition Republican People's Party (CHP) won control of the capital Ankara, and Istanbul, the biggest city and economic hub, for the first time in 25 years in local elections on March 31.
The mayoral certificate of the CHP's Ekrem Imamoglu has also been cancelled by the council.
The ruling Justice and Development Party (AKP) and their allies Nationalist Movement Party (MHP) have called for the results in Istanbul to be annulled, citing what they say "irregularities."
The rulings of the YSK are final. Initial results by the YSK have shown that the difference between candidates from CHP and AKP is around 14,000 votes.
The uncertainty over the results in Istanbul, which accounts for around a third of the country's economy, has kept financial markets on edge, as Turkey tries to recover from a currency crisis that saw the lira lose more than 30% of its value last year and another 10% this year.
The Turkish currency lost more than 2.5% against the greenback on Monday, extending its losses since the start of the year, touching the lowest level in seven months.
CHP deputy chair Onursal Adiguzel said on Twitter the ruling was "neither democratic nor legitimate." The re-run showed it was "illegal to win against the AKP." His party convened an emergency meeting Monday evening.
The YSK has ordered recounts across Istanbul and in its interim ruling it ordered district electoral officials to inspect their respective polling station officials.
Prosecutors also launched probes into alleged irregularities, which Anadolu Agency said resulted in 43 officials being linked to the network of U.S.-based cleric Fethullah Gulen, blamed by Ankara for a 2016 coup attempt against Erdogan.
The opposition dismissed the allegations as being an excuse for the government's refusal to acknowledge defeat.
On Saturday, Erdogan weighed in on the issue and signaled he favors a re-run of the Istanbul elections, which he said were marred by controversy and irregularities, adding that renewing the vote would allow the YSK to "clear its name."
Istanbul's new CHP mayor, Ekrem Imamoglu, who was granted certificate on April 17 after days of controversy, said on Saturday that the objections were unreasonable and they could "only laugh at this."
Imamoglu will now have to give away his office to an interim mayor.
CHP leader Kemal Kilicdaroglu has said the Istanbul elections had turned into a test for Turkish democracy.
Erdogan had accused the opposition of supporting "terrorism" and labeled the local election a "matter of survival" for Turkey during his campaign, which was held amid growing disenchantment among voters over economic woes.