Turkish politician Ekrem Imamoglu formally took office as mayor of Istanbul on Thursday after his victory in a repeat election.
Cheered by thousands of supporters of his Republican People's Party, Mr Imamoglu returned to Istanbul city hall to take the seat he was forced to give up when his win on March 31 was nullified.
"The people of Istanbul have confirmed their attachment to the Republic and to democracy," he told the jubilant, flag-waving crowd.
"This confirmation has shown the world that Turkey isn't any ordinary Middle East country. The belief in democracy runs deep in Turkey's veins."
Mr Imamoglu had won the first election by a narrow margin, but Turkey's top electoral body, ruling in favour of President Recep Tayyip Erdogan's governing party, annulled the result after he had served for 18 days.
The cancellation raised concerns about democracy in Turkey, where Mr Erdogan is accused of increasing authoritarianism.
In a rebuke to the ruling party, voters returned Mr Imamoglu to office with 54.21 per cent of the vote – 806,000 votes more than the governing Justice and Development Party's candidate, former prime minister Binali Yildirim.
In his speech, which was interrupted by chants of "Mayor Ekrem" and his campaign slogan "Everything will be beautiful", Mr Imamoglu promised to end wasteful spending of the city's public funds by the governing party.
"The squandering will end, the belt-tightening will start. Istanbul's 16 million will share the city's blessings," he said.
Earlier, authorities at Istanbul's main court presented Mr Imamoglu with a framed certificate confirming his mandate to rule over Turkey's largest city and commercial centre for the next five years.
Istanbul's governor Ali Yerlikaya the interim mayor, later handed over the municipality's official seal to Mr Imamoglu in a televised ceremony.
