Bogota  - In their first formal reaction to the loss of their most valuable hostages, leftist Colombian rebels Friday blamed the recent "escape" on a betrayal by two guerrilla members and warned the government of consequences for future such attempts.

The Revolutionary Armed Forces of Colombia (FARC) lost their most high-profile hostage, Ingrid Betancourt, and 14 others in a daring theatrical rescue by Colombian commandos.

In a statement, FARC said the rebels known with the aliases "Cesar" and "Enrique" - arrested last week in the operation that freed the hostages - betrayed the group.

"The escape of the 15 prisoners of war on Wednesday July 2 was the direct consequence of the despicable conduct of 'Cesar' and 'Enrique,' who betrayed their revolutionary commitment and the trust that had been put in them," FARC said.

The statement, dated July 5, was released Friday by the news agency ABP, a usual outlet for FARC comment. It was signed by the seven-member rebel leadership, and it constituted the group's first explicit reaction to the loss of their most valuable hostages.

The rebels said they will insist on their "policy of carrying out humanitarian agreements" with Colombian authorities.

However, FARC stressed that if the Colombian government wants to "persist on rescue as the only way" to obtain the release of the hostages, it should accept "all the consequences of its rash and adventurous decision."

The United States have requested the extradition of Gerardo Aguilar, alias "Cesar," and Alexander Farfan, alias "Enrique Gafas," over the kidnapping of three US contractors who were rescued alongside Betancourt.

The official version of events says that the Colombian military secured their release following a risky intelligence operation in which rebels were tricked into handing over their hostages for a pretended transfer.

Colombian authorities have emphatically denied reports of ransom payments to secure the rescue. (dpa)