He said Venezuelan authorities should ask Farc to explain "since they were the ones who betrayed them by offering to free a few hostages and then not keeping their promise".

 

Last month Hugo Chavez, the Venezuelan president, got together five leftist Latin American leaders and US film-maker Oliver Stone to witness the pickup of three hostages.

 

Clara Rojas, a former vice-presidential candidate, her three-year-old son Emmanuel and a former congresswoman was supposed to have been released on New Year's Eve.

 

The Farc blamed operations by Colombia's US-backed military for calling off the release but the government said the real reason could be that the boy was actually already in foster care in Bogota.

 

Last week DNA results confirmed Emmanuel was fathered by one of Rojas's captors.

 

In a statement late last week, the Farc said it still plans to follow through on its promise to release the two women.