The court said on Sunday that Imamoglu and at least 20 others were jailed as part of a corruption investigation, one of the two probes that were opened last week against the Istanbul mayor, who is the main political rival to President Recep Tayyip Erdogan.  

The court’s decision is expected to ignite further protests against the government, with the mayor’s supporters saying that the charges are politically motivated and undemocratic.

The government says that the probes are not politicized, emphasizing that courts are independent in Turkey.

Imamoglu, who is leading in some polls against Erdogan, has vehemently denied the allegations against him, describing them as unimaginable accusations.

Also on Sunday, Turkey’s main opposition group, the Republican People's Party (CHP) voted to nominate the mayor as their candidate for the next presidential election, although no general elections are set until 2028.

Reacting to Imamoglu’s imprisonment, thousands of people held a protest rally in Istanbul, leading to skirmishes with police, who used tear gas and water cannons to disperse the crowd.

Turkish authorities have reported the imprisonment of 323 protesters amid the demonstrations.