BOGOTA (AFP) - Recorded confessions made by the man who was Colombia's most wanted drug lord before his arrest have been stolen, in another blow to his latest trial, officials said on Saturday (Feb 19).

The recordings of Dairo Antonio Usuga, also known as "Otoniel", were made on Wednesday by a member of the Truth Commission, the body investigating a decades-long conflict between the government and the Revolutionary Armed Forces of Colombia (FARC) that ended with a 2016 peace deal.

The commission reported that on Feb 18, "unidentified persons entered the investigator's home at night", according to a statement.

"In the incident... the digital recorders that were used in the interview and a computer were stolen," it said.

The commission had already stressed on Thursday the need to have "guarantees" that Otoniel's testimonies were received "in confidentiality", after various media outlets reported police officers were present during the interrogations.

Police interrupted a hearing for Otoniel on Thursday, arguing there were concerns he was planning to escape.

The Truth Commission also asked authorities and the international community, including the United Nations, for conditions to continue investigating "without intimidation".

Usuga, 50, was arrested in October in north-west Colombia's dense jungle during an operation involving some 700 uniformed agents backed by 18 helicopters.

The government of conservative Ivan Duque has expressed its intention that he be extradited soon to the United States, where he is wanted on drug trafficking charges.

Otoniel has been convicted in Colombia on charges including drug trafficking, homicide, terrorism, recruitment of minors and kidnapping.

He led the Clan del Golfo, Colombia's largest drug gang, which exports some 300 tonnes of cocaine annually, according to official data.

Colombia is officially at peace after signing a pact with the FARC guerrilla group in 2016 to end more than half-a-century of armed conflict.

But it has seen a flareup of violence in recent months due to fighting over territory and resources by dissident guerrillas, the ELN rebel group, paramilitary forces and drug cartels.