Colombian President Juan Manuel Santos has suspended visits to Colombia by the negotiators of the Marxist rebel group FARC.
Colombian leaders and the rebel negotiators have been working on a peace deal in talks in Cuba.
Santos initiated the suspension after the negotiators — Ivan Marquez, Jesus Santrich and Joaquin Gomez — participated in a public event in Colombia with armed guerrillas standing close by, despite restrictions on such activities.
'No politics with arms'
Humberto de la Calle, chief government negotiator, said in a statement "For the government, a fundamental rule of this agreement is that there will be no politics with arms... This is an unacceptable violation."
De la Calle said the government has asked the International Red Cross to facilitate the return of the rebel leaders to Cuba "as soon as possible."
Colombia and FARC have announced their intention to file a peace agreement by March 23.
The leftist FARC rebels have been fighting a guerrilla war to topple Colombian governments since 1964, killing more than 220,000. They have used drug trafficking and kidnappings for ransom to fund their war.
Colombia's rebel movement has been weakened in recent years, and right-wing paramilitary forces formed to counter leftist fighters have been disbanded.
The Bogota government estimated FARC had about 16,000 fighters in 2001. But analysts say that number may have dropped to as low as 7,000 in recent years, largely because of desertions.