BOGOTA, COLOMBIA, NOV. 26 -- Hard-line Marxist guerrillas have kidnapped two Colombian and three American petroleum engineers, the state oil company said today.

A spokesman for Ecopetrol, the Colombian state oil company, said the five engineers were seized by three heavily armed guerrillas from the National Liberation Army (ELN) Sunday from a northern oil field near Venezuela. One of the Colombians was freed Sunday night and provided the information. No conditions for the release of the others were made public.

The spokesman said the Americans worked for National Tank Co. of Tulsa, Okla., under contract to steam-clean oil tanks. Spokeswoman Debi Hafner, in a telephone interview, confirmed the kidnappings and identified the Americans as John Bagby and Gary Sams of Tulsa and Robert Hogan of Bakersfield, Calif.

The ELN, which has 5,000 people under arms, has made Ecopetrol the focus of its anti-government campaign, repeatedly blowing up sections of Colombia's main oil pipelines. The group previously has kidnapped government officials and petroleum workers for ransom.

Authorities have charged that a faction of the ELN helped the Medellin cocaine cartel, for a payment, abduct six journalists on Aug. 30. Three other journalists were kidnapped separately in an attempt to press the government into negotiations. The traffickers have offered to turn themselves in if the government guarantees they will not be extradited and if they are granted special prisoner status.

Today, the Medellin cartel freed one of the nine journalists, editor Juan Vitta of Hoy por Hoy magazine, saying it acted because he was "suffering a severe deterioration of his health." Vitta, 48, has a heart condition, according to his family.