Ugandan President Yoweri Museveni has signed legislation that allows military tribunals to try civilians, parliament said on Monday, a move opposition leaders said violates a Supreme Court ruling.

Rights campaigners have long alleged that the government has used military courts to persecute political opponents of Museveni, who has been in power for almost 40 years.

His aides have denied this, saying only civilians who use guns for political violence are prosecuted in such tribunals.

In a ruling earlier this year, the East African country's Supreme Court banned the practice, calling it unconstitutional. It had been based on previous legislation that was challenged in lower courts.

Museveni's government subsequently introduced new legislation seeking to restore the prosecutions, and parliament subsequently passed it last month.

"President @KagutaMuseveni has assented to The Uganda Peoples' Defence Forces (Amendment) Act, 2025," parliament said in a post on the X platform.

After the bill's passage, the army's spokesperson praised it, saying it would "deter the formation of militant political groups that seek to subvert democratic processes".

The opposition says the new law violates the Supreme Court verdict. Ugandan courts could intervene again if they receive a citizens' petition against the legislation.

The earlier top court verdict forced authorities to transfer the military trial of a major opposition figure, Kizza Besigye, for alleged offences including treason, to a civilian court.

Pop star-turned-politician Bobi Wine, Uganda's biggest opposition figure, is preparing to challenge Museveni in next year's election. He was once charged in a military tribunal over illegal possession of guns, but the charges were later dropped.