Thousands of Sudanese rallied in several cities including the capital Khartoum on Monday, urging the country's new authorities to dissolve the former ruling party of ousted Islamist leader Omar al-Bashir.

Crowds of men and women rallied in Khartoum, its twin city of Omdurman, Madani, Al-Obeid, Port Sudan and in the town of Zalinge in war-torn Darfur, expressing their support for the new authorities who are tasked with the country's transition to a civilian rule.

Monday's gatherings also marked the October 21, 1964 uprising that had ousted the then military leader Ibrahim Abboud.

The demonstrators carried banners saying "Dissolve the National Congress Party", an AFP correspondent reported.

The rallies, organised by the umbrella protest movement Forces of Freedom and Change, was also meant to demand "justice for the martyrs" killed during the months-long uprising that led to Bashir's ouster in April.

Some Islamist groups had also called for similar gatherings on Monday in Khartoum but no major rally was reported, witnesses said.

Bashir and his Islamist National Congress Party ruled Sudan for three decades since 1989 when he came to power in an Islamist-backed coup.

Protests had erupted against his government in December 2018, and quickly turned into a nationwide movement against him that finally led to his ouster.

The protest movement says more than 250 people were killed in the uprising. Officials have given a lower death toll.

Bashir is being held in a prison in Khartoum and on trial on charges of corruption.

Several other officials of his government and senior party members are also in jail.