Heavy rain in southern Colombia has delayed an operation to collect a soldier who left-wing rebels have promised to release after 12 years.

Sgt Pablo Emilio Moncayo was just 19 when he was seized by Farc guerrillas.

The rebels unilaterally freed another soldier on Sunday but are still holding some 20 members of the security forces.

It is not clear how long the mission will be delayed but two helicopters are set to fly from the city of Florencia to the agreed handover location.

Colombia’s peace commissioner, Frank Pearl, said the decision to take off would be down to the crew of the two helicopters loaned by Brazil.