The latest protests came with US envoy to the Horn of Africa David Satterfield and Assistant Secretary of State for African Affairs Molly Phee expected in Khartoum early this week to push a message of "justice" for the Sudanese.

Demonstrators carrying the Sudanese flag gathered in central Khartoum as well as Wad Madani, a city to the south.

Security officers who deployed in large numbers fired volleys of tear gas, a regular tactic at the Khartoum protesters heading toward the presidential palace, an AFP correspondent said.

Sawsan Salah, from the capital's twin city of Omdurman, said protesters burnt car tyres and carried photos of people killed during other demonstrations since the October 25 military takeover.

In Wad Madani, "around 2,000 people took to the streets as they called for civilian rule," said Emad Mohammed, a witness there.

Protesters -- sometimes numbering in the tens of thousands -- have regularly taken to the streets despite a deadly security clampdown and periodic cuts to communications since the putsch led by army general Abdel Fattah al-Burhan.

The military takeover triggered wide international condemnation and derailed a fragile transition to civilian rule following the April 2019 ouster of longtime autocratic president Omar al-Bashir.

The crackdown has so far killed at least 64 people, and left hundreds wounded, according to an independent group of medics.

On Thursday, Sudanese authorities said protesters stabbed to death a police general, the first fatality among security forces.

Authorities have repeatedly denied using live ammunition in confronting demonstrators and insist scores of security personnel have been wounded during protests that have often "deviated from peacefulness".

- Diplomatic efforts -

Starting Monday in Riyadh, Satterfield and Phee were to meet the Friends of Sudan, a group calling for the restoration of the country's transitional government.

The meeting aims to "marshal international support" for the UN mission to "facilitate a renewed civilian-led transition to democracy" in Sudan, according to a State Department announcement.

The diplomats then travel to Khartoum for meetings with pro-democracy activists, civic groups, military and political figures.

"Their message will be clear: the United States is committed to freedom, peace, and justice for the Sudanese people," the State Department said.

The United Nations last week said it will launch talks involving political, military and social actors to help resolve the crisis.

The mainstream civilian faction of the Forces for Freedom and Change, the leading civilian pro-democracy group, has said it would accept the UN offer for talks if it were to revive the transition to civilian rule.

Proposed talks have been welcomed by the ruling Sovereign Council, formed by Burhan following the military takeover with himself as chairman.

Burhan has insisted that the military takeover "was not a military takeover" but only meant to "rectify the course of the Sudanese transition.

Earlier this month, Sudan's civilian prime minister Abdalla Hamdok resigned saying the country was now at a "dangerous crossroads threatening its very survival".