In a statement posted on its website Monday, Colombia's second largest guerilla group said it had seized two men several weeks ago in the north of the country.

The National Liberation Army (ELN) identified the captives as Uwe Breuer and Gunther Otto Breuer. The ELN also said it presumed the men were from Germany and that in the absence of an explanation for their presence in the turbulent Catatumbo region, they were being treated as spies.

"In the weeks they have been held, they have not been able to justify their presence in the territory, for which reason they are considered, for now, to be intelligence agents and will continue to be investigated," the statement said. "Spies are not protected by the international human rights convention."

The group did not offer precise details on when the men were captured or under what circumstances. But it noted that "no institution or person has publicly complained about the disappearance of these people."

The German Embassy in Bogota was unable to verify the claims, while a foreign ministry spokesman in Berlin said early on Tuesday that it was "pursuing the issue" and was "in contract with all relevant parties."

Peace talks sought

The ELN statement comes just weeks after two Canadian and two Peruvian gold mining workers were kidnapped in the remote San Lucas mountains of nearby Bolivar state. They were among six hostages taken by the ELN on January 18.

The group has reportedly sought to step up pressure on the Colombian government in a bid to be included in peace talks with FARC rebels. Negations between the government and the Revolutionary Armed Forces of Colombia designed to end five decades of conflict began in Cuba in November.

Last year, ELN chief Nicolas Rodriguez told news agency Reuters that he was willing to hold unconditional peace talks following failed attempts between 2002 and 2007. But it has so far refused to halt its campaign of kidnapping, bomb attacks and extortion ahead of negotiations.

The leftist group was formed in 1965, inspired by the Cuban revolution and is now thought to number less than 2,000 fighters. The ELN is considered a terrorist group by the United States and the European Union.

ccp/msh (AFP, Reuters)