Ugandan Foreign Minister Sam Kutesa, who is set to take over the presidency of the United Nations General Assembly on Wednesday, has a decades-long legacy of corruption, military aggression and human-rights abuses, according to opponents of his selection as ceremonial head of the world body.

The 65-year-old career politician and longtime ally of Uganda's controversial president, Yoweri Museveni, was unanimously chosen by the African Union last month to fill the rotating U.N. presidency during the continent's yearlong term at the helm.

There will be no vote at the U.N. before the mantle passes to Kutesa. But his selection has stirred an 11th-hour campaign to prevent him from taking office and presiding over General Assembly sessions, including the annual meeting of all 193 member states in September, when President Obama and other world leaders address the gathering.

Milton Allimadi, a Ugandan journalist based in New York and editor of the Black Star News website, has been circulating an online petition appealing to the U.S. State Department to revoke Kutesa's visa so he cannot attend Wednesday's administrative session, where he is to assume his presidential duties.

In his petition, Allimadi accuses his country's top diplomat of being a partner in Museveni's alleged crimes of "domestic repression in Uganda and multiple invasions of neighboring countries" that have caused millions of deaths in Rwanda, the Democratic Republic of Congo, and South Sudan.

Kutesa also defended Museveni's introduction of an anti-gay law last year that imposes life sentences to those convicted of "aggravated homosexuality," a charge applied to same-sex couples openly living together. Those who promote gay rights or help homosexuals evade detection can also face up to seven years in prison under the law.

Elevating Kutesa to the prestigious role of U.N. General Assembly leader and host "would be a mockery of all the ideals that the U.N. is supposed to stand for," Allimadi says in his petition, which has drawn more than 3,000 signatures.

U.S. Sens. Kirsten Gillibrand and Charles Schumer, who represent the state of New York, the seat of the United Nations, have also expressed concerns about Kutesa's assuming the post.

"It would be disturbing to see the foreign minister of a country that passed an unjust, harsh and discriminatory law based on sexual orientation preside over the U.N. General Assembly," Gillibrand said.

Schumer suggested that the U.N. "review Mr. Kutesa's participation" in enacting the anti-gay law, noting that the U.N. Charter "clearly promotes respect for human rights and for fundamental freedoms for all, without distinction as to race, sex, language, or religion."

Homosexuality has been outlawed in Uganda since it was a British colony. But the punitive law enacted in December has been associated with a 10-fold increase in attacks on gays in the conservative country, the group Sexual Minorities Uganda attested in a report last month carried by Britain's Guardian newspaper.

Human rights groups that castigated the anti-gay law when it was enacted in February have also criticized the choice of Kutesa to head the General Assembly.

"There are real concerns about Sam Kutesa's commitment to the values embodied in the Universal Declaration of Human Rights, including his defense of Uganda's profoundly discriminatory anti-homosexuality law," said Human Rights Watch Africa expert Maria Burnett.

A spokesman for the U.S. State Department's Bureau of Africa Affairs, Will Stevens, said he was not aware whether the petition had been presented to Secretary of State John F. Kerry

Uganda's U.N. mission envoys have declined to comment on the controversy, although Western news agencies in the Ugandan capital, Kampala, have reported that Kutesa has rejected the criticism of his nearly three decades in government as based on "a lie."