Some 25,000 people have been confined in their villages in the Colombian Amazon and risk running out of food as tensions soar between two guerrilla groups, a local governor said Thursday.

"Confrontation is imminent" between the two dissident groups, which split from the Revolutionary Armed Forces of Colombia (FARC) after it signed a peace deal with the government in 2016, the governor of the southern Caqueta region Luis Francisco Ruiz told Blu Radio.

He said the two groups, the Central General Staff (EMC) and the Segunda Marquetalia had imposed a "restriction on movement" on two key rivers, impacting two Indigenous communities who live near the triple border between Colombia, Ecuador and Peru.

"Nobody can travel via the river... lest innocents should fall. Nobody move," said an audio message broadcast on local media, attributed to a guerilla leader. AFP could not verify its authenticity.

A local community leader, speaking on condition of anonymity, said there had been "pamphlets" dropped in the streets from the armed groups, without giving more details. "It's very dangerous to go out," she said.

"We are talking about approximately 25,000 people" in an area where "the only access at the moment is by water," said the governor Ruiz.

In the past 10 days, only two barges carrying non-perishable goods were able to enter the area.

Otherwise there is "zero commercial transport" taking place.

Hugo Fiz Palacios, an official with the International Committee of the Red Cross in the region said the organization was "sharing our concern about the situation with the armed actors."

On Monday, Indigenous communities asked President Gustavo Petro's government to find "immediate solutions to the constant acts of confinement, threats, and impact to the free movement of communities" in the area.

"What we are seeing here is that we have no control over the Caqueta river," said Ruiz.

Restriction of movement is a longstanding problem in remote regions of Colombia, where illegal armed groups operate and exert control.

The Norwegian Refugee Council says such confinements have only increased since the peace deal was signed in 2016, and mainly impact Indigenous and Afro-Colombians.

Trapping communities not only cuts off their access to food, but prevents children from going to school and limits humanitarian access.

Petro has sought to put an end to six decades of conflict between the country's security forces, guerrillas, right-wing paramilitaries and drug gangs.

Since he took office in 2022, he has launched peace talks with the National Liberation Army (ELN) and the most powerful FARC dissident group, the EMC.

The EMC counts some 3,500 fighters and has been holding talks with the government since October.

Segunda Marquetalia has 1,600 men under the command of former FARC senior commander Ivan Marquez, who took part in the peace deal before taking up arms again in 2019, according to military intelligence sources.

© Agence France-Presse