Sudan's National Intelligence and Security Service has announced the release of all political prisoners across the country, state news agency SUNA reported on Thursday.
Shortly after the announcement, Twitter users circulated photos showing former detainees being welcomed by protesters as they joined demonstrations against Omar al-Bashir.
Protesters have been waiting for a statement from Sudan's military, as sources said Bashir had been forced to step down from the presidency after three decades in power and moves were under way to form a transitional council.
One of those released was Mohammed Naji Elasam, a spokesman for the Sudanese Professionals Association (SPA), the main organizer of protests being held across Sudan since December, witnesses said. Elasam had been detained for more than three months.