Turks punished President Tayyip Erdogan and his party on Sunday in nationwide local elections that reasserted the opposition as a political force and reinforced Istanbul Mayor Ekrem Imamoglu as the president's chief future rival.

With more than half of votes counted, Imamoglu led by nearly 10 percentage points in the mayoral race in Istanbul, Turkey's largest city, while his Republican People's Party (CHP) retained Ankara and gained nine other mayoral seats in big cities nationwide.

Analysts said Erdogan and his AK Party (AKP) - which have ruled Turkey for more than two decades - fared worse than polls predicted due to soaring inflation, dissatisfied Islamist voters and, in Istanbul, Imamoglu's appeal beyond the CHP's secular base.

"The favour and trust our citizens have in us have indeed been demonstrated," said Imamoglu, 53, a former businessman who entered politics in 2008 and is now seen by analsyts as a potential presidential challenger.

In Ankara, the capital, thousands of supporters gathered into the night waving CHP flags for a speech by CHP Mayor Mansur Yavas, who trounced his AKP challenger in another blow for Erdogan.

Erdogan had campaigned hard ahead of the municipal elections, which analysts described as a gauge of both his support and the opposition's durability. The president's disappointing showing could signal a change in the major emerging economy's divided political landscape.

Hours after voting ended, the president was headed to Ankara from Istanbul to address the nation.

According to 79.77% of ballot boxes opened in Istanbul, Europe's largest city with more than 16 million people, Imamoglu had 50.53% support compared with 40.73% for AKP challenger Murat Kurum, a former minister in Erdogan's national government.

Polls had predicted a tight contest in Istanbul and possible CHP losses across the country.

Yet partial official results reported by state-run Anadolu Agency showed AKP and its main ally giving up mayoralties in 10 big cities including Bursa and Balikesir in the industrialised northwest.

The CHP is leading nationwide by almost 1% of the votes, a first in 35 years, the results showed.

Mert Arslanalp, assistant professor of political science at Istanbul's Bogazici University, said it was Erdogan's "severest election defeat" since coming to national power in 2002.

"Imamoglu demonstrated he could reach across the deep socio-political divisions that define Turkey's opposition electorate even without their institutional support," he said. "This makes him the most politically competitive rival to Erdogan's regime at the national level."

IMAMOGLU'S RISE

In 2019, Imamoglu had dealt Erdogan a sharp electoral blow when he first won Istanbul, ending 25 years of rule in the city by AKP and its Islamist predecessors, including Erdogan's own run as its mayor in the 1990s. CHP also won Ankara that year.

The president struck back in 2023 by securing re-election and a parliamentary majority with his nationalist allies, despite a years-long cost-of-living crisis.

Analysts said the economic strains, including nearly 70% inflation and a slowdown in growth brought on by an aggressive monetary-tightening regime, moved voters to punish AKP this time.

"The economy was the decisive factor," said Hakan Akbas, a senior adviser at the Albright Stonebridge Group. "Turkish people demanded change and Imamoglu is now the default nemesis to President Erdogan."

Flag-waving supporters in front of the Istanbul Municipality building said they wanted to see Imamoglu challenge Erdogan for the presidency in the future.

"We are very happy. I love him so much. We would like to see him as president," said Esra, a housewife.

Rising popular support for the Islamist New Welfare Party, which took an even more hardline stance than Erdogan against Israel over the Gaza conflict, also sapped AKP support. The party took Sanliurfa from an AKP incumbant in the southeast.

Imamoglu was reelected despite the collapse of the opposition alliance that failed to topple Erdogan last year.

The main pro-Kurdish party, which backed Imamoglu in 2019, fielded its own candidate under the DEM banner in Istanbul this time. But many Kurds put aside party loyalty and voted for him again, the results suggest.

In the mainly Kurdish southeast, DEM reaffirmed its strength, winning 10 provinces. Following previous elections, the state has replaced pro-Kurdish mayors with state-appointed "trustees" following previous elections over alleged militant ties.

Violence erupted earlier in the day, including one incident in the southeast in clashes by groups armed with guns, sticks and stones, killing one and wounding 11. In another, one neighbourhood official, or "muhtar", candidate was killed and four people were wounded in a fight, Anadolu reported.

Several others were hurt in other incidents while one person was shot dead and two were wounded overnight ahead of the vote in Bursa, Demiroren reported.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)