Colombia’s President Gustavo Petro has warned that an attack on a military base in eastern Colombia “practically closes” peace talks.

Petro late on Tuesday blamed the leftist National Liberation Army (ELN) rebel group for the attack in Puerto Jordan, in the northeastern Arauca province, earlier in the day, which killed two soldiers and injured at least 21.

“This is an attack that practically closes a peace process, with blood,” he said during a ceremony in Bogota.

The ELN fired rockets from a cargo truck loaded with explosives in what the military called the most serious attack since a bilateral ceasefire between the government and the rebel group ended in August.

Six decades of conflict

The ELN, which has an estimated 6,000 fighters, is the biggest of the armed groups active in Colombia’s six-decade conflict, which has left more than 450,000 dead.

The government sealed a peace agreement with the Revolutionary Armed Forces of Colombia (FARC) in 2016.

Petro, the country’s first left-wing president, restarted peace talks with the ELN at the end of 2022 as part of his efforts to deliver “total peace”.

However, the talks have been in crisis for months as the group continued to conduct kidnappings and tax civilians in areas under its control.

The ELN has also expressed frustration that the government has opened separate talks with a splinter ELN unit in the southwest of the country.

In August, Defence Minister Ivan Velasquez said the military would resume operations against ELN after the ceasefire ran out.

The ELN accuses the government of failing to meet the terms of agreements signed during previous rounds of peace talks.

The group is also demanding that the government remove it from its list of organised armed groups.