0754 GMT November 20, 2019
State media reported that seven people were killed as tens of thousands rallied to demand a civilian government, while medics linked to the protest movement said five protesters had been killed, AFP reported.
The northeast African country's protesters have been calling for the departure of generals who seized power following the April ouster of longtime president Omar al-Bashir.
Sunday's "million man" march had been seen as a test for protest organizers after a June 3 raid on a Khartoum protest camp left dozens dead and a subsequent internet blackout curbed their ability to mobilize support.
But that did not prevent vast crowds of men and women, chanting slogans demanding "civilian rule", flooding the streets of Khartoum, twin city Omdurman and other towns and cities, AFP correspondents and witnesses reported.
Security forces meanwhile deployed en masse in key Khartoum squares, firing tear gas in several places including at protesters attempting to reach the capital's residential palace.
The official news agency SUNA quoted a Health Ministry official saying seven people were killed, without giving further details but adding that another 181 were wounded, including 27 by gunfire.
It also said a further 10 security personnel were wounded, including three from the feared paramilitary Rapid Support Forces, shot with "live ammunition".
Protest leaders blamed the generals for Sunday's bloodshed.
"The military council is completely responsible for these lives lost," prominent protest leader Mohamed Naji al-Assam said in a video posted on his Facebook page.
"Peaceful Sudanese protesters are exposed to excessive violence, live bullets and beatings," he said.
The generals in turn blamed the protest movement, the Alliance for Freedom and Change, for Sunday's violence.
Tension remains high between the protest leaders and generals since the June 3 raid, when armed men in military fatigues shot demonstrators who had camped for weeks outside army headquarters.
According to the doctors' committee, at least 133 people have been killed since the raid, including more than 100 on the day of the crackdown.
The raid came after talks between the protesters and generals collapsed over installing civilian rule.
Ethiopia and the African Union have been mediating between the two sides but have yet to achieve a breakthrough.