Members of Sudan's powerful paramilitary Rapid Support Forces prevented protest leaders from addressing journalists on Saturday, the eve of a mass rally against the ruling generals, protest organizers said.
Sudan's umbrella protest movement, the Alliance for Freedom and Change, has called for a "million man" march Sunday in Khartoum and its twin city, Omdurman, against the ruling generals, who have resisted calls to cede power to civilians.
The movement's key group, the Sudanese Professionals Association, had called for a media briefing on Saturday evening to unveil plans for the rally, but it was blocked by members of the RSF, protest leader Ahmed al-Rabie said.
"Before we could start the press conference, three vehicles from RSF, full of armed men, came to our building and told us not to hold the press conference," Rabie said.
They "also ordered all the people there to leave the building," he added.
A Sudanese journalist at the site confirmed that armed men had prevented him and other journalists from attending the briefing in Khartoum's eastern district of Burri, a hotbed of protests.
Rabie said two leaders from the movement had been arrested on Friday.
Sunday's mass protest is the first such rally called by the alliance since a deadly crackdown on a protest camp on June 3 left dozens dead and hundreds killed.
Tensions remain high between the two sides despite Ethiopian and African Union efforts to mediate a solution to the crisis.
Sudan's generals seized power after the army ousted longtime ruler Omar al-Bashir on April 11 following months of protests against his rule spearheaded by the Alliance for Freedom and Change. But they have since resisted calls to hand power to civilians.