A Colombian guerrilla group has offered to exchange the seven foreign tourists that it is holding for rebels held in prison.

Members of the ELN, or National Liberation Army, kidnapped the tourists, a Briton, a German, a Spaniard and four Israelis, as they walked in the Sierra Nevada mountains over three weeks ago.

One British man managed to escape last week and is now back home in England.

One of the ELN’s commanders, Pablo Beltran, made the rebel group’s first statement about terms for the possible release of the foreign hostages. It said that an exchange would be possible with rebels held in prison.

Hostage taking in Colombia is a frequent occurrence. Other rebel groups have held some prisoners for over five years, offering to release them only in exchange for members held in prison. But this is the first time the ELN has used the tactic.

Currently three Catholic priests are making their way to the Sierra Nevada to meet ELN guerrillas and visit the kidnapped tourists. They want to persuade the kidnappers to release their hostages although little hope is held for their success.