Dozens were injured and 72 arrested during a May Day march Wednesday in the Turkish capital, marking a shift from recent years of peaceful demonstrations on that national holiday.
Twenty-two police were among the injured, the governor of Istanbul province, Hüseyin Avni Mutlu, said.
Eight people - five officers and three civilians - remain hospitalized, he said.
Avni Mutlu praised the "discipline and restraint" of the 22,000 cops involved in the security operation and attributed the violence to "a fringe group of 3,000 or 5,000 people."
Authorities' decision to prohibit marches to the downtown Taksim Square, which is being renovated, and unions' insistence on marching to that emblematic site led to the disturbances.
The clashes began early Wednesday roughly a mile from the square when riot police in gas masks stopped the marchers' advance at key intersections.
Groups of young people hurled rocks at police, who responded with tear gas and water cannons during the hours-long standoff.
Finally, the unions abandoned their attempt to penetrate the police cordon and ended their protests with a rally at the city's Besiktas Square.
Wednesday's events in Istanbul constitute "state terrorism," Ismail Hakki Tombul, secretary general of the KESK public employees union, told Efe.
Several unions had spent days trying to secure permission from authorities to demonstrate in Taksim Square, a symbol of labor resistance since police gunned down 36 workers there in 1977.
May Day marches to Taksim Square have great symbolic significance for Turkey's workers' movement because the 1980s military dictatorship prohibited them.
The ban on May Day rallies in the emblematic plaza was lifted in 2009, and peaceful, festive gatherings drawing between 100,000 and 200,000 people had been held each year since. EFE