Journalists' groups on Tuesday demanded that Sudan release two reporters, an Egyptian and a Sudanese, who were detained one week ago during a clampdown sparked by unprecedented anti-regime protests.
The official Sudanese Journalists' Union said Shaimaa Adil, of the Egyptian Al Watan newspaper, and Marwa Al Tegani, should be either freed or brought before a court for the allegations against them to be disclosed at a transparent trial.
"We need to know the accusations," Mekki Elmograbi, the union's press freedom and human rights secretary, told AFP.
The state security agency reported that the Egyptian was in good health, but rejected the union's demand for a visit, he added.
The New York-based Committee to Protect Journalists (CPJ) said Adil and Tegani, a freelancer, were detained after covering anti-government protests and should be immediately released.
"The whereabouts or any charges against the journalists have not been disclosed," the watchdog said.
"Sudan believes it can silence reporting of political unrest by disappearing journalists into an informational black hole," CPJ deputy director Robert Mahoney said in a statement.
"Authorities in Sudan have stepped up their harassment of journalists in recent weeks," CPJ added.