TURKEY’S main opposition party retained its control over key cities and made huge gains elsewhere in Sunday’s local elections, according to official results.

The outcome of the local elections is a major setback for right-wing President Recep Tayyip Erdogan.

The incumbent Istanbul Mayor Ekrem Imamoglu, of the Republican People’s Party (CHP) looks to have won by a wide margin in Turkey’s largest city and economic hub, according to the Anadolu Agency. 

Mansur Yavas, the mayor of the capital, Ankara, retained his seat with a stunning 25-point difference over his challenger.

Outside Ankara City Hall, where a large crowd gathered to celebrate the victory, supporters chanted “Ankara is proud of you!”

CHP won the municipalities across 36 of Turkey’s 81 provinces, according to the Anadolu Agency, making inroads into former strongholds for Mr Erdogan’s party. 

It gained 37 per cent of the vote nationwide, compared to 36 per cent for the president’s party in a 76 per cent turnout, marking the CHP’s greatest electoral victory since Mr Erdogan came to power two decades ago.

Mr Erdogan acknowledged the electoral setback in a speech delivered from the balcony of the presidential palace, saying his party had suffered “a loss of altitude” across Turkey. The people delivered a “message” that his party will “analyse” by engaging in “courageous” self-criticism, he said.

Mr Erdogan added: “We will correct our mistakes and redress our shortcomings.”

He vowed to press ahead with an economic programme introduced last year aiming to combat inflation, which rose to 67 per cent in February.

Mr Erdogan has allowed borrowing costs to rise to 50 per cent in a bid to combat soaring prices.

The result came as a boost for the opposition, which was divided and demoralised after a defeat to Mr Erdogan and his ruling Justice and Development Party (AKP), in last year’s presidential and parliamentary elections.

“The voters decided to establish a new political order in Turkey,” CHP leader Ozgur Ozel told a crowd of jubilant supporters. 

The pro-Kurdish Peoples’ Equality and Democracy Party was on course to win many municipalities in the country’s south-east region. 

But in previous years, Mr Erdogan’s government removed elected pro-Kurdish mayors from office for alleged links to Kurdish resistance fighters and replaced them with state-appointed trustees.

Up to 61 million people, including more than a million first-time voters, were eligible to cast ballots for all metropolitan municipalities, town and district mayorships as well as neighbourhood administrations.