Turkish police fired water cannon and rubber pellets to disperse a crowd gathered in central Istanbul on Sunday for the city's annual gay pride parade.
It was not immediately clear why the police stopped the marchers gathering. The parade has been held in Istanbul in previous years, leading some to dub it the largest gay pride event in the Muslim world.
However, this year the timing of the parade coincides with the holy month of Ramadan, something that could cause conservative Muslims to bristle.
Turkey's Dogan news agency reported that police told crowds to disperse soon after they began assembling, telling them they would not be allowed to march.
The police appeared intent on stopping the crowd gathering near Taksim Square, the cameraman said. Taksim is a traditional rallying ground for demonstrators and saw weeks of unrest in 2013.
While homosexuality is not a crime in Turkey, unlike other Muslim countries, homophobia remains widespread.