The governor of Istanbul has banned gay, lesbian and transgender individuals from holding pride parades at their usual venue, citing security concerns.
Marches departing from the Turkish city's iconic Taksim neighbourhood will not be allowed "for the safety of our citizens and the participants".
The LGBT community has called for demonstrations on June 19 and June 26, which mark the beginning and end of pride week.
Turkish Islamist and ultra-nationalist groups have threatened counter-demonstrations to stop the parade from taking place.
Istanbul pride week organisers issued a statement with a #LoveWillWin hashtag in Turkish rejecting security concerns as a reason to ban the parades.
It said "the governorship prefers to limit people's rights and freedoms instead of taking measures to deal with the threats".
"It is crucial for us to be visible and at the centre of our cities at least for one day of the year," the statement added.
Istanbul's pride parade has been celebrated every year since 2003 with participants converging in Taksim. Last year, the march was banned and police used tear gas and water cannons to disperse the crowds.
The governor's office said it had suggested alternative venues for the celebration this year, but did not specify which ones.
The parade organisers have not said yet if they are willing to move the event to another location.
Istanbul has witnessed a series of deadly bombings in the past year including two suicide attacks targeting tourists. One of them hit the same crowded thoroughfare of Istiklal Avenue where the pride parade is usually held.
Western diplomatic missions in Turkey have been warning their citizens to avoid large gatherings for months.
The US consulate in Istanbul this week unfurled the rainbow flag in celebration of gay pride, but also to honour the victims of the bloody rampage at a gay nightclub in Orlando that left 49 people dead.
The massacre coincided with events celebrating Lesbian, Gay, Bisexual and Transgender Pride Month in the United States.
Turkey's pride parade organisers said they wanted to gather "after the tragedy in Orlando, to show once again we are united, strong and organised".
— Los Angeles Times (@latimes) June 17, 2016