Updated

The Philippine president has formally declared that communist guerrillas waging a decades-long rebellion are terrorists, in his latest move jeopardizing the resumption of peace talks with the insurgents.

President Rodrigo Duterte's spokesman, Harry Roque, told reporters Tuesday that the Philippine leader signed a declaration that the Communist Party of the Philippines and its armed wing, the New People's Army, are a terrorist organization, in the first step of a legal process to officially ban them.

If approved by a court, the communist guerrillas will be the second group to be proscribed under a seldom-used anti-terror law after the Abu Sayyaf, a brutal Muslim extremist group that was blacklisted in 2015 for involvement in ransom kidnappings, beheadings and bombings.