The protests, which began last week, demanded the withdrawal of a controversial tax reform proposed by the government of President Ivan Duque, who said Sunday the legislation would be retracted.
Demonstrations continued on Sunday in the capital, Bogota, and other cities including Medellin and Cali despite the announcement.
“Colombia faces particular threats from criminal organizations that are behind these violent acts,” Defense Minister Diego Molano said at a press conference, adding the vandals are not those marching peacefully.
Molano cited intelligence information in his allegation but did not offer further evidence.
Vandals were financed and organized by leftist guerrillas of the National Liberation Army (ELN) and former FARC rebels who reject a 2016 peace deal, Molano added.
“We are saddened for all those who lost their lives due to criminal actions during these protests,” Molano said.
He would not give specific details on the death toll, saying the attorney general’s office would investigate.
The national human rights ombudsman has reported 16 civilians and one police officer were killed during five days of protests, while the procurator’s office on Sunday said it is investigating connections between the protests and 14 violent deaths.
A local human rights group has reported more than 20 deaths.
Twenty-six allegations of police brutality during the protests are being investigated, said General Jorge Luis Vargas, director of Colombia’s national police.
Truck drivers’ and taxi drivers’ unions, which had threatened to join protests on Monday, backed out of strikes following the withdrawal of the tax reform.
Bogota Mayor Claudia Lopez said 25% of the capital’s mass transit system was out of service following vandalism and urged those who attended marches to get tested for COVID-19.
One major union said in a message on Twitter it would hold another national strike on Wednesday to protest a health reform, among other things.