Organisers of nationwide protests against Sudan's President Omar al-Bashir called on Khartoum residents on Thursday to mass at army headquarters as state media said the army would make an “important statement”.

"We call on our people from across the Khartoum capital and the region around to immediately go to the sit-in area and not leave from there until our next statement is issued," the Sudanese Professionals Association said.

A sit-in outside army headquarters, which also houses Bashir's residence, entered its sixth day on Thursday with protesters gathered in what the European Union has described as "an unprecedented number".