Opponents of a military coup in Sudan have called for nationwide protests on Saturday to demand the restoration of a civilian-led government to put the country back on a path to democracy after decades of authoritarian rule.

Thousands of Sudanese have already taken to the streets this week to protest against General Abdel Fattah al-Burhan ousting Prime Minister Abdalla Hamdok's cabinet in a coup that led Western states to freeze hundreds of millions in aid.

With at least 11 protesters killed in clashes with security forces, opponents of the junta fear a full-blown crackdown and more bloodshed.

"The army should go back to its barracks and give the leadership to Hamdok," said an activist who gave his name as Mohamed, who plans to protest. "Our demand is a civilian country, a democratic country, nothing less than that."

The United States, which is calling for the restoration of the civilian-led government, said how the army reacts on Saturday will be a test of its intentions.

"We call on the security forces to refrain from any and all violence against protesters and to fully respect the citizens' right to demonstrate peacefully," said a senior State Department official, briefing reporters on condition of anonymity.

US Secretary of State Antony Blinken said Sudan’s security forces must respect human rights and any violence against peaceful demonstrators was "unacceptable".

The United States continues to stand with "Sudan’s people in their nonviolent struggle for democracy", he said on Twitter.

The UN Special Representative in Sudan, Volker Perthes, said in a statement that he remained in constant contact with all sides to facilitate a political solution.

With internet and phone lines restricted by the authorities, opponents of the coup have sought to mobilise for the protest using fliers, SMS messages, graffiti, and neighbourhood rallies.

Neighbourhood-based resistance committees, active since the uprising against deposed President Omar al-Bashir that began in December 2018, have been central to organising despite the arrests of key politicians.

Bashir, who ran Sudan for nearly three decades, was deposed by the army following months of protests against his rule.

Khartoum committee activist Hussam Ibnauf he was confident of a big turnout. There was now "no fear factor", he said.

"Everyone on the street ... they know about October 30. If they know, the rest is easy," he said.

No debt relief

Burhan has said he removed the cabinet to avert civil war after civilian politicians stoked hostility to the armed forces.

He says he is still committed to a democratic transition, including elections in July 2023.

Hamdok, an economist, was initially held at Burhan's residence when soldiers rounded up the government on Monday, but was allowed to return home under guard on Tuesday.

The US State Department official said he was, however, still under house arrest and unable to resume his work.

The US official said tens of billions of dollars of debt relief sought by Sudan would not happen as long as the army was attempting to direct Sudan unilaterally. The United States and the World Bank have already frozen assistance to Sudan, where an economic crisis has seen shortages of basic goods including food and medicine and where nearly a third of the population are in need of urgent humanitarian support.

Several mediation efforts have emerged but there has been no sign of progress towards a compromise.

Western states are not looking to engage with the military or mediate any negotiation until detainees are released and the army shows commitment to power-sharing as set out in a transitional constitutional declaration, a Western diplomat said.

Many Sudanese opponents of the coup oppose a compromise with an army of which they are deeply mistrustful following several coups since independence in 1956.

"All those who accept or participate in dialogue with the military do not have the street's support," the Sudanese Professionals Association said in a statement, demanding a full handover of power to civilians.

Magdi El Gizouli, a political analyst, said Burhan's calculation is that he can suppress the opposition by force if needed, while counting on the backing of people who crave stability.