The tear gas was fired as demonstrators were heading toward the presidential palace in the capital Khartoum, in the latest rally against the October power grab led by army chief Abdel Fattah al-Burhan, the correspondent said.

Mass protests have been regular in Sudan since the power grab which derailed the country's rocky transition to civilian rule following the 2019 ouster of autocratic president Omar al-Bashir.

At least 79 people have been killed and hundreds wounded in the crackdown on anti-power grab demonstrations, according to an independent group of medics.

Monday's protests took place despite heavy security presence in Khartoum and its neighbouring cities of Omdurman and Khartoum North.

It came only two days after thousands of pro-military demonstrators rallied against recent UN talks that aimed to help Sudan resolve the political crisis since the power grab.

On Monday, anti-power grab protesters in the city of Wad Madani, south of Khartoum, were seen waving the Sudanese flags and carrying posters of people killed in the crackdown.

"No, no to military rule" and "blood for blood," they chanted, according to witnesses.

Hundreds also gathered in the Red Sea city of Port Sudan, residents there said.

In Khartoum, some protesters also called for the dissolution of the powerful paramilitary Rapid Support Forces commanded by Burhan's deputy, Mohamed Hamdan Daglo, an AFP correspondent said.

"The Janjaweed should be dissolved," the protesters chanted, in reference to the RSF which grew out of the Janjaweed militias accused by rights groups of atrocities in Darfur.

Sudan, which was already in the grip of a dire economic crisis before the power grab, has seen vital foreign aid cut as part of the international community's condemnation of the takeover.

The United States, which suspended $700 million in assistance to Sudan after the power grab, has warned that a continued crackdown by the authorities would have "consequences".

Sudanese authorities have repeatedly denied using live ammunition against demonstrators, reporting scores of security officers have been wounded and a police general was stabbed to death.

On Monday, the Sudanese Professionals Association, which called for anti-power grab protests, said the latest demonstrations were "a message to the dictatorship that authority lies with the people".