ISTANBUL: Waving flags and chanting slogans, hundreds of thousands of anti-government demonstrators rallied in Istanbul Saturday calling for democracy to be defended after the arrest of mayor Ekrem Imamoglu which sparked Turkey's worst street unrest in over a decade.

Under a cloudless blue sky, huge crowds gathered in Maltepe on the Asian side of Turkiye's biggest city on the eve of the Aidilfitri celebration which starts Sunday, marking the end of Ramadan.

Ozgur Ozel, leader of the main opposition party CHP which organised the rally, said there were 2.2 million people in the crowd, but AFP was unable to independently confirm the figures.

"I'm not scared. I've only got one life, I'm ready to sacrifice it for this country," said an 82-year-old woman in a headscarf, carrying a picture of Imamoglu and the Turkish flag.

She did not want to give her name "in case they come knocking at my door".

"He's an honest man, he's the one who will save the Turkish republic," she said of the mayor who was arrested then jailed over a graft probe on charges widely believed to be spurious.