"From now on I will consider the CPP-NPA-NDF a terrorist group," Duterte said at the wake of three soldiers in northern Mindanao killed in an ambush by NPA rebels, according to a local media outlet.
The acronyms refer to the Communist Party of the Philippines, the New People's Army, and the National Democratic Front.
The announcement follows suspended peace talks with the communists and Duterte telling authorities to get released NDF political prisoners who attended the recent talks in Norway and Rome back in prison.
Last year, the U.S. State Department designated the Communist Party of the Philippines and its armed wing, the NPA, as a foreign terrorist organization.
Duterte’s backtracking on the prisoners’ release came after he ended the cease-fire with New People's Army rebels who earlier killed seven soldiers and captured three others.
Duterte late Saturday explained that with the suspension of peace talks, the NDF negotiators' amnesty will be revoked, saying, "They are on the wanted list, so I'll cancel their passports."
Duterte stressed any amnesty could come only after successful talks and not before.
The government was supposed to resume formal peace talks with the NDF representatives this April in Oslo.