Suspected leftist rebels kidnapped about 90 workers from a US oil firm Occidental Petroleum Corp yesterday, it was reported.
It is one of the country's biggest mass kidnappings, an army official said.
Gen Carlos Lemos said in an interview with local radio Radionet the Occidental employees were abducted while travelling in convoy to their homes from the Cano Limon oil field in the eastern province of Arauca.
Gen Lemos said Colombia's second-largest rebel force, the National Liberation Army (ELN) was suspected of orchestrating the abduction.
"The personnel that live in Arauca, of which there are some 92 people, are presumed kidnapped," Mr Lemos said.
Occidental officials could not be immediately reached for comment.
The ELN, which is accused of escalating a rigorous bombing campaign of the Cano Limon oil field in past months, recently announced its peace talks with the government were in crisis over suspected collusion between army troops and far-right paramilitaries.
Rebels use ransom money to fund their decades-old war against the state.