Colombia's military says 57 soldiers have been kidnapped by civilians in the country's south-western Micay Canyon area.

It says 31 soldiers were seized on Saturday while the rest were abducted on Sunday by a group of more than 200 people.

The military says the civilians are acting under pressure from dissidents of the Farc rebel group, which agreed a peace deal with the government in 2016.

The mountainous region is a key zone for cocaine production and remains one of the most tense in the country's ongoing conflict with rebel groups.

In a video statement on social media, Brig Gen Federico Alberto Mejía said four non-commissioned officers and 53 soldiers had been seized over the weekend.

"This is called kidnapping," he said.

Reports in local media suggest that the EMC rebel group - the largest offshoot of the Farc - may have ordered the kidnappings.

The EMC has not commented on the issue.

General Erik Rodríguez told Colombian newspaper El Tiempo that the incident had been triggered by the arrest of a suspected EMC rebel on Saturday.

As the soldiers prepared to airlift the suspect out of the mountainous area, the general explained, they were surrounded by more than 100 people.

A second military unit was then seized the following day by an even larger group of locals, he said.

All of the soldiers are being held at the same location and negotiations are under way to ensure their speedy release, Gen Rodríguez said.

The Micay Canyon is used for transporting cocaine to Pacific ports, after which drugs are then illegally shipped to other countries.

The Colombian military said it had been present in the area since October, "on constant patrol" and "capturing and neutralising armed combatants".

According to estimates by the military, more than 90% of the inhabitants of the area depend on the cultivation of coca bushes - the plant used to make cocaine - for a living.

Gen Rodríguez said that the soldiers were seized because their presence in the area was seen as a direct threat to the illegal cocaine trade which flourishes there.

The Colombian government, under the leadership of left-wing President Gustavo Petro, has held peace negotiations with the EMC rebel group, but its main leader, known as Iván Mordisco, walked out of the talks last year as EMC split into warring factions.

Under Mordisco's leadership, the rebels engage in criminal activities such as the extortion of farmers and landowners, illegal mining and cocaine trafficking.