CAIRO - An international rights group on Monday urged the United Nations to investigate alleged violations by Sudan's security forces against anti-government protesters.

Sudan has been gripped by nationwide protests since Dec. 19. The demonstrations were triggered by rising prices and shortages but quickly turned to calls for autocratic President Omar al-Bashir to step down. Human Rights Watch called on the U.N. Human Rights Council to respond to the crisis at its March session.

The New York-based group says it obtained video footage that shows "government forces' extreme violence and shocking abuses against protesters."

"There is irrefutable evidence that Sudan is using ruthless violence and brutality against peaceful protesters and critics of the government," said Jehanne Henry, associate Africa director at HRW. "It is high time for the U.N. Human Rights Council to ramp up monitoring and reporting on the situation and to send investigators to the country at once."

Authorities in Sudan have used tear gas, rubber bullets, live ammunition and batons to quell the unrest. They have imposed emergency laws and night-time curfews in some cities, and have suspended classes in schools and universities in others. They have arrested opposition leaders, doctors, journalists, lawyers and students along with some 800 protesters.

Last month, authorities ordered the release of all protesters who were detained since Dec. 19. But Human Rights Watch said only 186 were reported released and that video evidence showed signs of torture on released detainees.

Hundreds of demonstrators gathered Sunday in Sudan's capital and other cities calling for al-Bashir's ouster, according to an umbrella of independent professional unions which organizes the protests.

Activists say at least 57 people have been killed in the protests. The government's latest tally stands at 30 killed, but figures have not been updated in days.

Al-Bashir, who seized power in a military coup in 1989, insists that only elections, which he intends to run in, could bring change.

News from © The Associated Press, 2019