Authorities in Istanbul have banned gay, lesbian and transgender people from holding pride marches this month, citing security concerns for citizens and participants.
Turkish Islamist and nationalist groups had threatened to stop such parades from taking place, claiming that they would not allow "degenerates" to hold the events on Turkish soil.
The organizers of the parade, the Pride Week Commission, said the ban was illegal and vowed to seek relief in court.
The LGBT community had called for demonstrations on two consecutive weekends.
A march in support of transgender people was planned for June 19 in central Istanbul, while the annual gay pride parade was scheduled for June 26.
Istanbul's pride parade has been celebrated every year since 2003, with participants departing from iconic Taksim Square.
The march was banned last year, and police used tear gas and water cannons to disperse crowds who defied the measure.
Security in Istanbul is already tight after a series of explosions in recent weeks claimed by Islamic State and Kurdish militants, or blamed on them.