The appearance of the posters in Ankara comes just over a week after Turkish police prevented Istanbul's annual gay pride march - a successful tradition in the last years - from going ahead and used water cannon against activists who showed defiance.
"Should those who practice the foul labor and adhere to the practice of the people of Lot be killed?" said the posters that appeared in the Turkish capital overnight.
The prophet Lot, who features in the Old Testament and the Koran, is decried by many Muslims for failing to halt the decline of the cities of Sodom and Gomorrah, which was blamed on the sexual preferences of their inhabitants.
A hitherto low-key Islamist group called the Young Islamic Defense claimed responsibility for the poster campaign through a Twitter account @islamimudafaa, saying it was trying to "respond to the immoral actions" of lesbians, gays and bisexuals.
The poster showed an image of a past gay pride march in Istanbul and the group said it was seeking to respond to such events.
The group said that the phrase used was a hudud - an Islamic concept - from the Koran.
Anti-riot police in Istanbul used teargas and fired rubber pellets to disperse thousands of participants in the city's Gay Pride march on June 28, with the authorities saying the event had not received the proper authorization.
Activists said that the authorities had tried to justify the ban by saying such an event could not take place during the Muslim holy month of Ramadan.
Homosexuality is not illegal in Turkey and unlike in many Muslim countries visible communities exist in the bigger cities, including Istanbul, Ankara and Izmir.
But many gays still keep their sexuality a secret for fear of a backlash from family or the general public, and remain at risk of unprovoked attacks.
Posted by Women Against Shariah on Wednesday, July 8, 2015
From the AFP via the Daily Star: