Colombia's leftist National Liberation Army (ELN) confirmed Tuesday that it was holding a soldier captured in an attack last week that killed 11 other government troops.

The ELN said Corporal Carlos Fabian Huertas was taken prisoner in the region of Norte de Santander after a 30-minute firefight, and was in good health.

The Colombian army had previously reported that 11 soldiers were killed and one was captured in the attack in Chitaga, a municipality in the northern province, which borders Venezuela.

"In fulfillment and out of respect for international humanitarian law, our forces gave dignified treatment to the wounded soldiers, as well as to the military prisoner," the ELN said in a statement on its website.

In the statement, the ELN also called for a cease-fire to build confidence in a peace process.

The ELN has been excluded from peace talks under way in Havana between the government and Revolutionary Armed Forces of Colombia, the country's largest leftist guerrilla group, with some 9,000 combatants.

The ELN is the country's second largest guerrilla group, with some 2,500 fighters.