The Sudanese authorities have arrested at about nine opposition leaders amid the fresh anti-government protests expected after the weekly Muslim prayers on Friday.
The head of the media office at the National Intelligence and Security Service denied any knowledge of the arrests. Sudan has been rocked by more than a week of anti-government protests sparked by rising prices, shortages of basic commodities and a cash crisis.
At least 19 people have died during the protests, including two military personnel, according to official figures.
However, rights group Amnesty International put the death toll at 37.
The arrests of opposition leaders occurred late on Thursday after security forces raided their meeting in the Sudanese capital, Khartoum, according to a statement by a committee of professional organisations involved in the protests.
The nine arrested included Siddiq Youssef, a senior leader of Sudan's Communist Party, as well as leaders from the pan-Arab Ba'ath and Nasserist parties, the statement said.
The arrest came after opposition groups called for more protests after the weekly noon prayers on Friday. Fourteen leaders of one of Sudan's two main opposition groupings were briefly held last Saturday.
The protests was attracting increased backing from political and civil society groups.
It is yet unclear if the government would allow the protests to go, given how they responded with tear gas and live ammunition Tuesday. That same measure might be taken today again that more live ammunition and tear gas will be used and that the death toll will rise."