ANKARA, Turkey -- Turkish President Recep Tayyip Erdogan insisted Tuesday that rerunning the Istanbul mayoral vote that was won by the opposition will only strengthen democracy, while critics called the decision an "outrageous" move to eliminate dissent against his government.
Ruling in favor of Erdogan's governing party, Turkey's top electoral body on Monday annulled the results of the March 31 vote in Istanbul, which opposition candidate Ekrem Imamoglu narrowly won, and scheduled a re-run for June 23.
"The will of the people has been trampled on," said Meral Aksener, leader of a nationalist party in Turkey that had backed Imamoglu.
The loss of Istanbul — and the capital of Ankara — in Turkey's local elections were sharp blows to Erdogan and his conservative, Islamic-based Justice and Development Party, or AKP.
AKP had challenged the results of the vote, claiming it was marred by irregularities. Critics accuse the AKP of trying to cling to power in Istanbul, a city of 15 million people that is Turkey's cultural and commercial hub, and of exerting heavy pressure on the country's electoral body to cancel the outcome of the March 31 vote.
The controversial decision has increased concerns over democracy and the rule of law in Turkey, a NATO member that is still formally a candidate to join the European Union. Turkey is also a key Western ally in the fight against terrorism and in stemming of the flow of refugees to Europe.
The move is raising questions about whether Erdogan, who has consolidated power throughout his 16 years in power and is increasingly accused of authoritarianism, would ever accept any electoral defeat or relinquish power.
"This outrageous decision highlights how Erdogan's Turkey is drifting toward a dictatorship," Guy Verhofstadt, a European Parliament lawmaker and the leader of the Alliance of Liberals and Democrats, said on Twitter.
Soner Cagaptay, director of the Turkish Research Program at the Washington Institute for Near East Policy, described the decision on Istanbul as a "seismic event in Turkish history."
"Turkey has been holding free and fair elections since the 1950s," he told The Associated Press. "Never before has a party refused to accept the outcome of the election... This goes against 70 years of accepted tradition."
"(Erdogan) is saying 'let's vote until the governing party wins," he added.
Manfred Weber, the leading conservative candidate seeking to head the European Union's executive branch, told n-tv television in his native Germany that he'd end EU membership negotiations with Turkey if he's elected later this month.
Weber, the center-right European People's Party candidate and front-runner to replace Jean-Claude Juncker as president of the European Commission, said Turkey's decision on the Istanbul vote was "incomprehensible for many of us in Europe."
"In the past years, Turkey has unfortunately alienated itself from the values of Europe," he said. "For me, that means ending the accession talks between Turkey and the European Union."
Turkish opposition newspaper Birgun branded the decision a "coup" and argued that justice in the country has "been suspended."
The redo of the Istanbul vote also threatens to further de-stabilize the Turkish economy, which has entered a recession.
The Turkish lira crashed spectacularly last summer over investor concerns about Erdogan's policies. It has been sliding again in recent weeks and on Tuesday it hit its lowest level since October.
Europe's top human rights and democracy watchdog also expressed concerns about reports of pressure exerted by Erdogan's government on the electoral body.
"We face the repeat elections in Istanbul with great concern and urge Turkish authorities to do their utmost to restore the safeguards of the electoral process," said Anders Knape, president of the Congress of Local and Regional Authorities of the Council of Europe.
Delivering a speech in Parliament on Tuesday, Erdogan reiterated that the vote was sullied by irregularities "we could not ignore." He rejected opposition accusations that his party was trying to win back a key election that it had lost.
He said violations included the alleged improper entering of election data and the fact that thousands of officials overseeing the vote at ballot stations were bankers or teachers and not civil servants, as required by law.
"We see this decision as an important step in strengthening our democracy, which will enable the removal of the shadow cast over the Istanbul election," Erdogan said.
The opposition, however, has complained about irregularities at Turkish elections in the past years, but their objections have been ignored.
Imamoglu arrived in Ankara on Tuesday for emergency talks with senior members of the opposition Republican Peoples' Party, or CHP. Despite media reports about a possible boycott, CHP made clear that Imamoglu would run again in the Istanbul race.
"We extend our hand to all our citizens," the party said. "We wholeheartedly believe that this extended hand will be held strong on 23 June, that it will strengthen our democratic struggle and that we will achieve a greater victory than on March 31."
On the other side, Erdogan told reporters that former Prime Minister Binali Yildirim would again run as the ruling party's candidate for mayor.
Also Tuesday, the Interior Ministry appointed Istanbul's governor Ali Yerlikaya as acting mayor of the city. The Istanbul municipality immediately deleted all tweets posted by Imamoglu during his 20 days in office as mayor.
David Rising in Berlin contributed.