The Sudanese Professionals Association (SPA), a body that led protests against former leader Omar al-Bashir, said the civil disobedience campaign will only end when the ruling generals "transfer power to a civil transitional authority in accordance with the Declaration of Freedom and Change (DFC)."
It added, in a statement released Saturday, that the campaign meant not going to work and "general civil disobedience for a civil state."
The call to action comes as several opposition leaders were arrested by security forces, a day after the Prime Minister of neighboring Ethiopia, Abiy Ahmed, held talks with Sudan's military rulers and opposition leaders in a bid to revive negotiations.
Security forces conducted an overnight raid on a residence Saturday and arrested Ismail Jalab and Mubarak al-Ardul, who are respectively Secretary-General and spokesperson of the rebel Sudan People's Liberation Movement-North (SPLM/N).
SPLM/N, which Bashir banned as a political party in 2011, said in a statement that the men were taken to an undisclosed location, CNN reported.
In a separate raid, security forces arrested Mohammad Esmat, a member of the Declaration of Freedom and Change Forces (DFCF), according to the Sudanese Congress Party in a Facebook statement.
The UK Ambassador to Sudan, Irfan Siddiq, called for the Transitional Military Council (TMC) to release "opposition leaders immediately," in a Saturday twitter post.
He also specified that two of the detained, SPLM/N's al-Ardul and Jalab, were arrested just a day after meeting with his deputy.
Refusal to talk
Protest leaders, including the SPA, have rejected talks with military leaders attempting to do damage control in the face of international criticism of Monday's indiscriminate killings.
SPA released a statement Thursday said negotiations could not start with the TMC "until those responsible for last week's barbaric attacks on demonstrators at the Army HQ are brought to justice."
One of the conditions would be the formation of an independent investigative committee supported internationally to launch an investigation into June 3 crackdown -- which saw more than 100 people killed and hundreds more injured when soldiers and paramilitary groups opened fire on a sit-in that has been ongoing since the dramatic fall of Bashir in April.
Dozens of bodies were pulled from the Nile Wednesday and the Central Committee of Sudan Doctors (CCSD), an organization of medical volunteers, said they had been weighed down with rocks in an attempt to hide the true death toll.
The official Sudanese Health Ministry has contested this total, saying the death toll was not over 46, according to state media.
After April's coup, the military council and opposition groups agreed on a three-year transition to democracy. But after talks broke down in May, and Monday's attack, coup leader Lt. Gen. Abdel Fattah al-Burhan called for national elections within nine months on Tuesday.
The only way to rule Sudan is through "the ballot box," he said in an address on state TV.
In a later speech, he said he regretted the violence and that "all involved in the events that lead to the disruption of the protests site will be held accountable and brought to justice."
The military presence in Khartoum and other cities remains high however, and there have been reports of the Rapid Support Forces, the notorious paramilitary group previously known as the Janjaweed militia, roaming the streets.