A Sudanese official has denied that at least 100 people were killed by a paramilitary unit during protests, saying that the number was at most 46.
Doctors linked to the opposition on Wednesday said at least 100 people had been killed in the capital, Khartoum, amid pro-democracy protests.
They said 40 bodies were pulled from the River Nile in Khartoum on Tuesday.
Authorities had initially stayed quiet, but a health ministry official put the number at 46 early on Thursday.
Sudanese opposition activists have rejected an offer of talks from the country's military council, saying it cannot be trusted amid a violent crackdown on protesters.
Residents told the BBC they were living in fear in the capital.
The deputy head of the military council defended the violent suppression, claiming that the protesters had been infiltrated by rogue elements and drug dealers.
"We will not allow chaos and we will not go back on our convictions. There is no way back. We must impose the respect of the country by law," said Mohammed Hamadan – also known as Hemedti – on Wednesday.
Numerous reports from Khartoum said the paramilitary unit, the feared Rapid Support Forces (RSF), was roaming the city's nearly deserted streets, targeting civilians.
Formerly known as the Janjaweed militia, the RSF gained notoriety for brutal atrocities in the Darfur conflict in western Sudan in 2003.
What was the lead-up to the latest violence?
Sudan has been controlled by a military council since pro-democracy protests led to the ousting of veteran President Omar al-Bashir in April, after 30 years of authoritarian rule.
Demonstrators had been occupying the square in front of the military headquarters, while their representatives had negotiated with the military council and agreed a three-year transition that would culminate in elections.
But on Monday, security forces swept in and opened fire on unarmed protesters in the square. General Abdel Fattah al-Burhan, the head of the military council, announced that the agreement was cancelled and an election would take place within nine months./BBC