President Gustavo Petro of Colombia suggested that the commander of the Estado Mayor Central rebel group, Ivan Mordisco, was planning to have him assassinated by snipers.
Relations between the government and certain factions of the EMC have reached new lows after a ceasefire between the two sides broke down in July.
Petro who made the post on X, did not give details and intelligence sources said they did not have information of the planned attack.
The EMC is a dissident group of the now-demobilized Revolutionary Armed Forces of Colombia (FARC) which rejected a 2016 peace deal with the state.