Ugandan security forces on Tuesday arrested dozens of people who tried to walk to the parliament building to demonstrate against high-level corruption in protests that authorities say are unlawful.

Police and the military deployed heavily in various parts of Kampala where small groups of protesters had gathered. Some campaigners were roughed up by police as they were forced into trucks. The police frequently use force to break up demonstrations by opposition leaders and others.

The protests are organized by Ugandans who hope to emulate efforts by people in neighbouring Kenya, whose street action recently forced the president to dismiss almost his entire cabinet after widespread opposition to a contentious tax proposal.

Ugandans have been provoked by mounting allegations of corruption against the parliament speaker, Anita Among, who has rejected calls for her resignation. The anti-corruption campaign started with revelations online of allegedly irregular expenditure by the office of the speaker and others close to her.

Among, a senior member of Uganda’s ruling party, has since been sanctioned by the U.S. and the U.K. She has denied any wrongdoing, and her supporters say she’s been unfairly targeted in a country where corruption is rampant among officials. She is now the subject of an official probe into the source of her wealth as well as charges she misused parliamentary resources.

Ugandan President Yoweri Museveni, an authoritarian leader who has been in power since 1986, said at the weekend that street protests were intolerable.

“We have defended the direction of Uganda’s revolutionary path in the past and we shall defend it even more now,” Museveni said in a televised address, warning protest organizers that they were “playing with fire.”

Museveni’s government has long been accused of shielding corrupt but influential officials from criminal prosecution. After his reelection to a sixth term in 2021, Museveni promised to crack down on corruption. But many Ugandans are not hopeful.

Local media outlets frequently report on corruption issues, but activists, opposition figures and others who try to stage street demonstrations face arrest under a law that requires them to first notify police of their plans to rally.