Protest leaders had reached agreement with the ruling military council on the other main aspects of the transition.
The generals and protest leaders had been expected to come to an agreement on Wednesday on the make-up of a ruling council.
The illegal use of social media by external parties to derail democratic processes in Africa is a growing concern.
The British ambassador to Khartoum said Sudanese security forces had fired at protesters.
The composition of the new sovereign council has been the toughest part of the negotiations.
A quarter of Algerians under 30 are unemployed and there have been regular protests in resource-rich centres.
Demonstrators converged on the military complex last month seeking the army's help in ousting Bashir.
Sudan's army rulers and protest leaders resumed crucial talks over handing power to a civilian administration