The African Union has suspended Sudan’s membership “with immediate effect”, amid an upsurge of violence in the capital that has seen dozens killed.
The pan-African body has warned of further action if power is not transferred to a civilian authority – a key demand of pro-democracy protesters.
Opposition activists say a paramilitary group has killed 108 people this week, but officials put the figure at 46.
Residents said pro-government militia were all over the capital Khartoum.
The violence intensified on Monday when security forces stormed a weeks-long sit-in outside military headquarters in the capital. It is the deadliest incident since veteran President Omar al-Bashir was ousted by the military in April after months of peaceful protests.
Talks between opposition activists and the ruling interim military council have since broken down. On Thursday the UK Foreign Office summoned the Sudanese ambassador to raise concerns about the developments.
“The AU Peace and Security Council has with immediate effect suspended the participation of the Republic of Sudan in all AU activities until the effective establishment of a Civilian-led Transitional Authority, as the only way to allow the Sudan to exit from the current crisis,” the AU tweeted on Thursday.
The decision was made unanimously by members at an emergency meeting of the AU in Addis Ababa that lasted more than five hours.
he chairman of the African Union commission, Moussa Faki Mahamat, on Monday called for an “immediate and transparent” investigation into the killings.
Ethiopian Prime Minister Abiy Ahmed was heading to Khartoum on Friday to try to mediate between the two sides, Reuters news agency reported, quoting diplomatic sources.
The Sudanese authorities spoke for the first time on Thursday about the death toll, denying that it was as high as 100 and saying it was “at most” 46. Doctors linked to the opposition said the figure was as high as 108, and that 40 bodies were pulled from the River Nile in Khartoum on Tuesday.
The deputy head of the military council, Mohamed Hamdan “Hemeti” Dagolo, defended the violent suppression, claiming that the protesters had been infiltrated by rogue elements and drug dealers.
Meanwhile, residents in Khartoum told the BBC they were living in fear, with much of the city in lockdown in the wake of the killings.
Numerous reports said a paramilitary unit, the feared Rapid Support Forces (RSF) commanded by Lt Gen Dagalo, was roaming the city’s nearly deserted streets on Monday, targeting civilians.
A number of women arrested by the RSF told the BBC that they were repeatedly beaten with sticks and threatened with execution. They said RSF troops told them to run for their lives, then opened fire. Other victims, they said, were forced to drink sewage water and urinated on.
Formerly known as the Janjaweed militia, the RSF gained notoriety for brutal atrocities in the Darfur conflict in western Sudan in 2003.