Sudan's security forces have been accused of using excessive violence during protests against military rule in the capital Khartoum.
A doctors' union allied to the protest movement said 178 demonstrators were injured on Saturday, and has accused security forces of using live bullets.
Sudanese authorities, meanwhile, said some 58 police officers had reported injuries during the demonstrations.
They added that more than 100 people had been arrested in the capital.
The pro-democracy demonstrations on Saturday saw thousands of protesters approach the presidential palace for the second time in a week, waving flags and chanting slogans against the military.
They were met by a heavy security presence, and tear gas was used to disperse the crowds.
There were also demonstrations in a number of other cities, including Port Sudan where there were reports of people being arrested and beaten.
Activists planned a series of street protests for Saturday - exactly two months since generals launched their takeover.
Last weekend, hundreds of thousands of demonstrators marched through Khartoum demanding civilian rule be restored after the military coup on 25 October.
More than 100 people were injured in clashes with police in last week's protests. The security forces were also accused of sexually abusing more than a dozen women and girls.
Coup leader Gen Abdel Fattah al-Burhan has defended October's military takeover, alleging that the army acted to prevent a civil war because political groups had been inciting civilians against the security forces.
He has said he remains committed to the transition to civilian rule, with elections planned for July 2023. However it is unclear how much power the new civilian government will have, as it will be subject to military oversight.
The general has also warned that protests could impede a smooth democratic transition.
Pro-democracy activists accuse the military of stealing the revolution that led to long-serving ruler Omar al-Bashir being ousted in 2019.