The decision blocks modifications to the peace deal, stymieing right-wing opponents of President Juan Manuel Santos who have long rejected the accord.
The group, also known the Usuga Clan, is accused of operating profitable drug trafficking routes in partnership with Mexican cartels.
The National Liberation Army (ELN) rebel group, which has bombed oil installations and kidnapped for ransom, was founded by radical Catholic priests in 1964.
Citizens gathered to pay homage to those who were killed in the blasts in Bogota last week, where violence against civilians is on the rise.
The remaining 40% are due to be relinquished by June 20.
Colombia’s Constitutional Court has struck down two provisions meant to speed approval of laws on the government’s peace deal with Marxist FARC rebels.
What can Colombia can learn from other nations’ transitions, both successful and unsuccessful, from war to peace?
“We call on all combatants who have been tricked into this futureless path to distance themselves from this mistaken decision taken by their commanders,” the statement said.
Colombia’s government and the FARC signed a peace accord in September that was rejected in a plebiscite last month.
The new deal limits the work of the special tribunals to ten years and requires any investigations be opened within the first two years.
Colombians rejected the accord with the FARC in a surprise plebiscite result this month.