Colombia’s President Gustavo Petro has blamed a ‘narco-terrorist group’ led by a former FARC fighter for the attack.

The death toll from a deadly highway bombing in southwestern Colombia has risen to at least 20, the governor of the Cauca region has said.

Governor Octavio Guzman said on Monday that the death toll included 15 women and five men.

There were also 36 people injured, including three who remained in intensive care as of Monday and “five minors who are out of danger”, Guzman said in an update shared on social media.

Some media reports put the death toll from the lethal explosion, near a tunnel on the Pan-American Highway, at 21 as of late on Monday.

A dozen of the victims were from a village near the town of Cajibio, where hundreds of mourners held a vigil on Monday.

The mourners were dressed in white and waved white sheets or balloons as a sign of peace.

“Please, no more death, no more violence,” Joao Valencia, 42, a relative of a woman killed in the attack, told the AFP news agency, holding up her picture.

“These kinds of women should die of old age, not have their lives taken from them in such a tragic way,” he added.

The bombing was one of the deadliest attacks in Colombia since the now-defunct Revolutionary Armed Forces of Colombia (FARC) blew up a Bogota nightclub in 2003, killing 36 people.

Colombia’s President Gustavo Petro said a “narco-terrorist group” was responsible for the attack, specifically naming a group led by Nestor Vera, commonly known as Ivan Mordisco, one of Colombia’s most wanted men.

Mordisco is a dissident former member of FARC, which signed a landmark peace agreement with the government in 2016.

The attack comes just more than a month before national elections, in which voters will pick a successor to President Gustavo Petro.

Security is one of the central issues of the May 31 presidential election, with a suspect recently arrested in the assassination of young conservative presidential hopeful Miguel Uribe Turbay last June.