Colombia's government and FARC rebel force warned that a court ruling on their recent peace accord threatens to disrupt efforts to seal an end to a half-century civil war.
Upholding a challenge by the political opposition, the Constitutional Court on Wednesday overruled two clauses of a legislative act passed in December to fast-track the peace deal.
"The government respects the court's decision but we do not agree with it," Interior Minister Juan Fernando Cristo told reporters on Thursday.
"We consider that this decision poses a difficulty on the path to implementing the peace."
The peace deal itself was signed in November following modifications after voters narrowly rejected it in a referendum.
Critics say the deal is too soft on FARC members, who may get reduced sentences for crimes committed during the conflict.
The leftist Revolutionary Armed Forces of Colombia (FARC) are disarming and preparing to transform into a political group under the deal.
Their leader Rodrigo Londono said on Twitter its members, who are assembled in disarmament zones, were gathering for discussions.
Analysts say the rejection of the fast-track procedure means the peace drive must be debated article by article, laying it open to amendments by lawmakers opposed to it.
The president of the Constitutional Court, Luis Guillermo Guerrero, said however that the ruling would not affect key parts of the accord that have already been passed into law.
Those include a law allowing amnesties and pardons for FARC members accused of certain "political" crimes.