Adana had been the setting for Saturday night clashes between Erdogan supporters and his opponents, who accuse him of gradually instituting authoritarian Islamic rule.
Stone-throwers attacked an anti-Erdogan demonstration, witnesses said.
The protests had taken their toll on the police, too, with six policemen committing suicide, media quoted Faruk Sezer, the president of the Emniyet-Sen police union as saying. The officers were forced to work shifts as long as 120 hours on the streets, he said.
Police violence against the demonstrators was a result of the violence experienced by the police themselves, Sezer said, adding that the union was collecting evidence with a view to initiating legal proceedings against police commanders.
Emniyet-Sen was founded last year against the resistance of police leadership and has indicated that from April this year has more than 7,000 members.
On Sunday, Taksim Square hosted a mass rally organized by the Taksim Platform, one of the groups behind the protests.
"We expect all citizens who plan to exercise their rights to their city, their Gezi Park and make their voices heard," the group said in a press statement. "We will continue until our demands are met."
In the capital, Ankara, police used water cannon and tear gas to disperse about 10,000 protesters from central Kizilay Square.
Devlet Bahceli, leader of the ultra-nationalist Nationalist Movement Party (MHP), which had announced its support for the protesters, backed opposition calls for new elections on Saturday, saying Erdogan had aggravated the crisis in the country and would have to renew his mandate.
Erdogan's party rejected the demands. "There is no reason for early elections. The government, parliament and cabinet work like clockwork," party spokesman Huseyin Celik said after a meeting of the party leadership in Istanbul.
©2013 Deutsche Presse-Agentur GmbH (Hamburg, Germany)