The United States said on Monday that the signing of an "abhorrent" anti-gay law by Uganda's President Yoweri Museveni marked a "sad day" for his country and the world.
Museveni signed the bill despite warnings from Washington that he was putting US relations with Kampala at risk and amid fears that aid donors could also react badly.
"Instead of standing on the side of freedom, justice, and equal rights for its people, today, regrettably, Ugandan President Museveni took Uganda a step backward by signing into law legislation criminalizing homosexuality," said White House spokesman Jay Carney in a statement.
"As President Obama has said, this law is more than an affront and a danger to the gay community in Uganda, it reflects poorly on the country's commitment to protecting the human rights of its people and will undermine public health, including efforts to fight HIV/AIDS."
Carney said Washington would continue to urge Uganda to repeal the "abhorrent" law.
The anti-gay bill cruised through parliament in December after its architects agreed to drop a death penalty clause.
It holds that repeat homosexuals should be jailed for life, outlaws the promotion of homosexuality and legally obliges people to denounce gays to the police.
Earlier, in a first US reaction, President Barack Obama's national security advisor Susan Rice weighed in against Museveni.
"Nobody should be discriminated against or punished for who they are or whom they love," Rice said on Twitter.
"Sad day for Uganda and the world," she added.