By Jeremy McDermott BBC correspondent in Bogota

Rescue efforts have been intensified as the kidnappers have been identified as members of the ELN or National Liberation Army.

In a statement the Colombian Episcopal Council expressed hoped that the ELN would release the hostages as soon as possible rather than face international condemnation.

The church says priests are on standby to meet guerrilla leaders.

HOSTAGES HELD Briton: Mark Henderson German: Reinhilt Weigel Israelis: Beni Daniel, Ortaz Ohayon, Ido Joseph Guy, Erez Altawil Spaniard: Asier Huegun

The announcement comes as security forces intensify their efforts to rescue the hostages.

The tourists were kidnapped over two weeks ago as they visited the ruins of the lost city.

Since then the captors are believed to have been marching southward as quickly as possible to reach the rebel mountain stronghold.

One hostage, 19-year-old Briton Matthew Scott, managed to escape from the rebels the day after the group were taken hostage.