The list included people who had previously not identified themselves as gay, just a day after president Yoweri Museveni enacted a punitive anti-homosexual law.
US Secretary of State John Kerry said Mr Museveni’s signing of the bill on Monday marked “a tragic day for Uganda and for all who care about the cause of human rights”.
He warned that Washington could cut aid to the East African nation over the discriminatory move.
“Now that this law has been enacted, we are beginning an internal review of our relationship with the government of Uganda to ensure that all dimensions of our engagement, including assistance programmes, uphold our anti-discrimination policies and principles and reflect our values,” Mr Kerry said.
The Red Pepper tabloid published the names – and some pictures – of alleged homosexuals in a front-page story under the headline: “EXPOSED!”
The list included Ugandan gay activists such as Pepe Julian Onziema, who has warned the new anti-gay law could spark attacks on homosexuals. A popular Ugandan hip-hop star and a Catholic priest were also listed.
Few Ugandans identify themselves publicly as gay, and the tabloid’s publication of alleged homosexuals recalled a similar list published in 2011 by a now-defunct tabloid that called for the gays to be executed. A Ugandan judge later condemned the outing of homosexuals, saying it amounted to an invasion of privacy.
A Ugandan gay activist, David Kato, was killed after that list came out, and activists said they believed he was targeted because of his work promoting gay rights.
“The media witchhunt is back,” tweeted Jacqueline Kasha, a Ugandan lesbian activist also listed in the Red Pepper story.
Uganda’s new-anti-gay law punishes gay sex with up to life in jail. The bill originally proposed the death penalty for “aggravated homosexuality”, defined as repeated gay sex between consenting adults and acts involving a minor, a disabled person or where one partner is infected with HIV.
First-time “offenders” also face life in jail, contrary to an earlier version of the bill that mentioned a 14-year jail term.
The new law also creates the offences of “conspiracy to commit homosexuality” as well as “aiding and abetting homosexuality”, both of which are punishable with seven years in jail. Those convicted of “promoting homosexuality” face similar punishment.
In signing the bill, Mr Museveni said the measure was needed because the West promotes homosexuality in Africa, rejecting international criticism as interference in Uganda’s internal affairs.
Mr Museveni accused “arrogant and careless western groups” of trying to recruit Ugandan children into homosexuality, but he did not name which groups he was alluding to.
Ugandan police spokesman Patrick Onyango said yesterday no homosexuals have been arrested since Mr Museveni signed the bill but that at least two had been taken into custody since parliament approved the bill last December.
Mr Onziema said he had counted up to six arrests and said more than a dozen Ugandan homosexuals had fled the country fearing for their safety.
Homosexuality has long been criminalised in Uganda under a colonial law that banned sex acts “against the order of nature”.
Some Ugandan lawyers and activists have said they will challenge the law in court as unconstitutional, unenforceable and impossible to implement.