The mayor of the Colombian capital, Bogotá, has imposed a curfew to cover the entire city in response to renewed anti-government protests.
Police fired tear gas in the city on Friday to disperse crowds and there were reports of sporadic looting.
Meanwhile, President Iván Duque said he would launch a "national conversation" next week to try to ease tensions.
More than 250,000 people attended marches across the country on Thursday to voice anger at the government.
Colombians have taken to the streets over possible changes to the minimum wage, pension and tax reforms, and the privatisation of state companies. The government insists there are no planned pension or labour reforms and that any changes would take place in consultation with labour groups.
Protesters are also angry about alleged corruption and what some see as the government's failure to honour a 2016 peace deal with left-wing Farc rebels amid a rise in violence.
In another development, three police officers were killed in a bomb explosion at a police station in the town of Santander de Quilichao in south-western Cauca province, officials said. It is not clear if the incident is connected to the protests. The area is notorious for drug trafficking and gang violence.