BOGOTA, Colombia—Colombia's defense minister says the country's armed forces will not honor a cease-fire that FARC rebels unilaterally declared as peace talks opened in Havana.

Defense Minister Juan Carlos Pinzon was responding to the announcement of a unilateral cease-fire earlier Monday by top rebel negotiator Ivan Marquez.

Marquez declared a two-month cease-fire effective Monday night.

Pinzon said in a brief statement to reporters in Bogota that Colombia's military has the "constitutional duty to pursue all criminals who have violated the Constitution."

He said that as a result, what he called "the terrorists" of the Revolutionary Armed Forces of Colombia would be pursued "for all the crimes they have committed over so many years."