Justice officials asked a court to formally designate the Communist Party of the Philippines and its armed wing, the New People's Army, as terrorist groups in a move that could further damage chances of a resumption of stalled peace talks.
In a petition before a Manila regional court, the Department of Justice cited deadly attacks and violence committed by the insurgents, including bloody internal purges of suspected military spies, in seeking the proscription of the groups behind one of Asia's longest-raging communist insurgency.
President Rodrigo Duterte resumed peace talks with the guerrillas after he rose to power in 2016. He granted concessions by appointing three left-wing activists to his cabinet, but the cordial relations rapidly deteriorated when he protested continuing rebel assaults on troops and policemen.
Last year, he cancelled Norwegian-brokered talks with the guerrillas and signed an order declaring the rebel groups as terrorist organisations in a prelude to his government's formal move on Wednesday.
Senior assistant state prosecutor Peter Ong said the guerrillas were insincere in their talks with the government and only wanted to grab power.
"Their main purpose is to mobilise all their forces in preparation for the 'people's war' aimed at overthrowing the duly constituted authorities," according to the justice department petition, adding that the rebels wanted to impose "a totalitarian regime".
If approved by the court, the proscription could serve as a legal weapon and basis for the government in securing court clearances to put rebel leaders and fighters under surveillance and freeze their bank accounts and assets, Mr Ong said.
Companies paying the so-called "revolutionary taxes" to the rebels could be questioned even though the military said such extortion demands have been done by coercion.
The volatile Philippine president has variously been hard line and soft on the guerrillas, but his most recent threats have been ruthless.
Human rights groups condemned him last week for saying that troops should shoot female communist rebels in the genitals to render them "useless". Mr Duterte has offered bounties to encourage government forces to kill the insurgents and on Monday suggested they could decapitate the rebels.
"No need to bring me the body. Bring me the head, put it in a Styrofoam, show it to me," he said. But in the same speech, he showed openness to resume peace talks, saying Norwegian officials flew to the Philippines to explore the possibility of a resumption of the peace talks.
"I have to consult my military people. Why? They're the ones being killed not me," Mr Duterte said. "I said: 'I will talk to the military. If you would agree, I might.'"
The communist rebel organisations are the second to be targeted by the Philippine government for proscription under a seldom-used 2007 anti-terrorism law. In 2015, a court approved a similar petition against the brutal Abu Sayyaf Islamic extremist group, which has also been blacklisted as such by the United States for kidnappings, beheadings and bombings.
The communist rebellion has raged for nearly half a century and left about 40,000 combatants and civilians dead. It also has stunted economic development, especially in the countryside, where the military said about 3,700 Maoist insurgents are still waging a guerrilla war.