Protesters and witnesses said that Sudanese soldiers intervened to protect protesters from Armed Forces which were trying to break up their sit-in in front of the Ministry of Defence.
Reuters reported that Armed Forces on pickup trucks fired tear gas at thousands of anti-government protesters.
In the meantime, Agence France-Presse (AFP) reported, quoting eyewitnesses that the Sudanese Armed Forces were deployed around the General Command in Khartoum.
In the early hours of the day, thousands of Sudanese arrived at the office of the Army's General Command to join the protesters after the spread of leaks about the government's intention to break-up their sit-in by force.
The demonstrators crossed the different bridges separating the capital from the cities of Bahri and Omdurman to join the protesters and support them. They chanted slogans calling for the overthrow of the regime.
The demonstrators said that their sit-in would continue until the regime falls, stressing their peaceful movement and asking the military institution, during last Saturday's massive demonstrations, to support their demands.
The German news agency quoted eyewitnesses as saying that, earlier, the Sudanese Army had also clashed with an armed force which tried to break up the sit-in.
Witnesses confirmed the occurrence of injuries by live bullets among the demonstrators without further specifying numbers. They said that the army confronted a large Armed Force which attacked the sit-in and fired sound bombs, live bullets and tear-gas on the demonstrators.
Following a meeting headed by Omar Al-Bashir, the National Defence and Security Council confirmed on Sunday that the protesters represent a segment of society which must be heard, Sudan News Agency reported.
The protesters are demanding President Al-Bashir to step down.