Security forces in Uganda have arrested the country’s main opposition figure, Robert Ssentamu popularly known as Bobi Wine.

Bobi Wine had last week called on Ugandans to “rise up peacefully and unarmed” in protest against President Yoweri Museveni, who has ruled the East African country for nearly four decades.

He was arrested during the protest when he led members of parliament against the torture of his supporters, according to a tweet posted on Monday by the administrators of his verified Twitter handle.

“Bobi Wine arrested as he led MPs and other leaders in a peaceful protest against the abduction, torture and murder of his supporters. The protest was taking place at City Square, Kampala. ~ ADMIN,” the tweet stated.

Museveni won a sixth term in office in January with 58 percent of the vote. His main rival was Wine, who came second with 35 percent and decried the election as rigged.

The singer-turned-lawmaker refused to accept the result and challenged it in court, saying he won the day. But the 39-year-old later withdrew his petition, saying the judiciary was stacked in favour of Museveni.

Speaking earlier at the headquarters of his National Unity Platform in Kampala, Wine said the time had come for public demonstrations against Museveni, who took power in 1986 and has ruled ever since.

“I call upon you to rise up peacefully and unarmed to demonstrate against the regime that has oppressed us, exploited us and turned us into slaves in our own country,” Wine had said.

Since the January 14 election, the opposition has alleged that security forces have been abducting their supporters.

Museveni and government officials initially denied these claims, but later admitted that citizens accusing of plotting against the state were being held by the military and other security agencies.

The police pre-emptively declared Wine’s call for protests illegal and warned “organisers of these unlawful demonstrations to desist from participating in any unlawful activities”.

“The police will not hesitate to arrest and charge in courts of law anyone, who will be found participating in these illegal activities,” Uganda’s police force said in a statement on Monday night.