Sudanese police fired tear gas as demonstrators marched in the capital Khartoum towards a prominent square to honour dozens of people killed in the months-long protest movement, Al Jazeera reports.

The rallies on Thursday came a day after protest leaders and army rulers signed a power-sharing deal to form a joint civilian-military body tasked with installing a civilian administration.

Reuters reports that the demonstrators rolled out a banner honouring fallen protesters, a symbolic move that left some in tears.

Reuters says thousands of demonstrators, mostly teenagers and people in their early 20s, joined a rally in the square, which continued to grow into the late afternoon. Protesters said they were renaming it from the Green Square to Freedom Square.

"The rallies are a tribute to those honourable 'martyrs' of the December revolution," the Sudanese Professionals Association said in a statement quoted by Al Jazeera.

Riot police fired tear gas to disperse a rally at a key bus station in downtown Khartoum, witnesses told Al Jazeera.