Sudanese demonstrators march and chant during a protest against the military takeover, in Atbara, Sudan in this social media image. [Reuters]

Military forces shot dead two people during nationwide protests in Sudan on Saturday, a doctors committee said, as hundreds of thousands of people demanded the restoration of a civilian-led government after a military coup.

Sudan's Central Doctors Committee said the two protesters were shot dead by troops in the capital Khartoum's twin city of Omdurman during demonstrations.

People carried Sudanese flags and chanted "Military rule can't be praised" and "This country is ours, and our government is civilian" as they marched in neighbourhoods across the capital.

Protesters also took to the streets in cities in central, eastern, northern and western Sudan. Crowds swelled to the hundreds of thousands in Khartoum, said a Reuters witness.

Thousands of Sudanese have already demonstrated this week against the ousting of Prime Minister Abdalla Hamdok's cabinet on Monday by General Abdel Fattah al-Burhan in a takeover that led Western states to freeze hundreds of millions of dollars in aid.

In central Khartoum on Saturday there was a heavy military deployment of armed troops that included the army and the paramilitary Rapid Support Forces.

Security forces had blocked roads leading to the defence ministry complex and the airport.

At least 11 protesters have been killed in clashes with security forces this week and opponents fear a full-blown crackdown.

In local neighbourhoods, protest groups blocked roads overnight with stones, bricks, tree branches and plastic pipes to try to keep the security forces out.

A 75-year-old man who gave his name as Moatez and who was walking the streets searching for bread said normal life had been brought to a complete halt in Khartoum. “Why did Burhan and the army put the country in this crisis? They could solve the problem without violence,” he said.

US WARNS AGAINST VIOLENCE

Unlike in previous protests, many people carried pictures of Hamdok, who remains popular despite an economic crisis that had worsened under his rule. "Hamdok is supported by the people. If Hamdok takes the country that's okay," said Mohamed, a member of a neighbourhood resistance committee.

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

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

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 forced out by the army following months of protests against his rule.

Protesters carried pictures of Burhan, his deputy General Mohamed Hamdan Dagalo, and Bashir covered in red.

"Close a street, close a bridge, Burhan we're coming straight to you," they chanted.

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 United States and the World Bank have already frozen assistance to Sudan, where an economic crisis has seen shortages of food and medicine and where nearly a third of the population are in need of urgent humanitarian support.