0653 GMT January 16, 2022
The Office of the United Nations High Commissioner for Human Rights voiced "profound shock" at a further incident overnight in the city of Cali, saying police "opened fire" on demonstrators, reportedly killing and injuring a number of people, according to AFP.
The rights office called for calm on all sides ahead of a planned mass protest on Wednesday, and stressed that security forces should only use firearms as a last resort.
Spokeswoman Marta Hurtado told reporters in Geneva that the situation remained volatile.
"What we can say clearly is that we have received reports, and we have witnesses, is (of) excessive use of force by security officers, shooting, live ammunition being used, beatings of demonstrators and as well detentions," she said.
Protesters in Colombia called Monday for a new mass rally after 19 people died and more than 800 were wounded in clashes during five days of demonstrations, according to official figures.
"Despite an announcement from the Colombian presidency on May 2 that the tax reform bill would be removed from Congress, the protests, which began on April 28, have been continuing, with calls for a massive demonstration on May 5," Hurtado said.
She said that "the majority of the protests to date have been peaceful."
"Given the extremely tense situation, with soldiers as well as police officers deployed to police the protest, we call for calm.
"We remind the state authorities of their responsibility to protect human rights, including the right to life and security of person, and to facilitate the exercise of the right to freedom of peaceful assembly.