Sudan’s Central Doctors Committee said the three protesters were killed by troops in the capital Khartoum’s twin city of Omdurman during the nationwide protests after a military coup.
But Sudanese police denied shooting the protesters, saying on state TV that one policeman sustained gunshot wounds.
People carried Sudanese flags and chanted “Military rule can’t be praised” and “This country is ours, and our government is civilian” as they marched in neighbourhoods across the capital.
The protesters have called for a return to a path to democracy and rejected military measures and demanded the release of detainees.
According to Sudan TV, Sudanese security forces closed the majority of main roads and bridges in Khartoum, with the exception of the Halfaya and Soba bridges.
People also took to the streets in cities in central, eastern, northern and western Sudan. Crowds swelled to the hundreds of thousands in Khartoum, said a Reuters witness.
“The people have delivered their message, that retreat is impossible and power belongs to the people,” said protester Haitham Mohamed.
“This has been a miscalculation from the start and misunderstanding of the level of commitment, bravery, and concern the street has about the future of Sudan,” said Jonas Horner of the International Crisis Group.
Civilian-appointed cabinet ministers supported the protests in a statement, and said the military “will not find free Sudanese or true democratic revolutionary forces to be their partners in power.”
In central Khartoum on Saturday there was a heavy military deployment of armed troops that included the army and the paramilitary Rapid Support Forces.
Tens of thousands of Sudanese this week protested General Abdel Fattah al-Burhan’s removal of Prime Minister Abdalla Hamdok’s cabinet on Monday, in a military takeover that triggered a deadly crackdown against protesters and led Western states to freeze hundreds of millions of dollars in aid.
