Uganda will not give equal rights to gays and lesbians nor has it plans to legalise homosexuality, Ethics Minister James Nsaba Buturo has said.
The gay activists in Kampala wore masks in case of recognition (photo: Katherine Elaine Roubos)
He was responding to a call from the Sexual Minorities Groups in Uganda (Smug) which for the first time held a press conference demanding recognition.
They also accused the police of brutality and harassment.
The gay community is estimated by activists to number 500,000 in Uganda where they face much discrimination.
The BBC's Joshua Mmali in the Ugandan capital, Kampala, said many of those present at the press conference on Thursday wore masks, fearing to show their faces.
Smug leader Victor Juliet Mukasa said she had been a victim of inhuman treatment.
She said police raided her home in 2005, took away documents and arrested her guest, whom they later forced to strip naked.
"We were treated in a degrading and inhumane way. Many of us have suffered similar injustice," she told journalists.
"We are here today to proclaim that these human rights violations are completely unacceptable. We have had enough of the abuse, neglect and violence."
But Mr Buturo told the BBC News website that homosexuality was "unnatural" and denied claims of police brutality and rights abuses.
"If they were being harassed, they would be in jail. We know them, we have details of who they are," he said.
At the press conference, gay activist Dr Paul Ssemugoma called for education on same sex-relationships to reduce the incidence of HIV and other sexually-transmitted diseases among the gay community.
Uganda has won praise for its vigorous campaign against HIV/Aids.
It has helped to reduce the prevalence of the virus - which reached 30% in the 1990s - to single-digit figures.
Activists also hit out at the church, accusing the clergy of demonising them.
A Kenyan gay man, who had travelled to Kampala to show solidarity with his Ugandan counterparts, said homosexuals in East Africa are forced to live double lives.
"These people are subjected into being in forced marriages to cover up, yet they suffer inside," he said.