Footage uploaded to social media shows Turkish police using tear gas and water cannons against a crowd gathering to march in an annual gay pride parade in Istanbul’s Taksim Square on Sunday.
Some of the videos show gay pride supporters being knocked off their feet from the force of the water, while others show marchers frantically trying to run away.
Reuters news agency has reported organisers of the parade had been refused permission to march this year because it coincided with the Muslim holy month of Ramadan.
Despite being refused permission to march, hundreds still gathered in Taksim Square, donned in colourful clothing and waving rainbow flags.
The parade has been held in the past and has been described as the biggest gay pride event in the Muslim world.
“These people do not hurl stones and they never would. They do not throw petrol bombs. They just ask for a legal recognition,” said one supporter, who gave his name as Bulent.
“This summarises what has been happening in Turkey. Any request for rights is met like this.”
One Instagram user, Hindasari, described how numerous police arrived and stood watching the event before unleashing the tear gas and water cannons to disperse the crowd.
The police action drew swift international condemnation on Twitter, including from singer and rights activist Lady Gaga who called on authorities to “set an example for people to celebrate both Ramadan and pride in peace, instead of dividing with violence”.
While homosexuality is not a crime in Turkey, it is generally considered taboo and homophobia is widespread.
The gay pride movement has gone global after voters in Ireland backed same-sex marriage by a landslide in a referendum last month.
The US followed suit on Saturday, as the Supreme Court ruled in favour of same-sex marriage to be recognised by the constitution. It is now legal in all 50 US states.
To celebrate the landmark decision, the White House was illuminated in rainbow colours, while its Twitter avatar was changed to the rainbow colours of the growing gay rights movement.
The movement has also spread around the world through social media with Facebook adding a feature that lets users superimpose the rainbow colours over their profile pictures.