Philippine President Rodrigo Duterte has angrily scrapped talks with communist insurgents aimed at ending their decades-long conflict after both the government and the rebels called off unilateral ceasefires.

Duterte, a self-described socialist who had previously freed top communist leaders to jump-start the peace talks, condemned the insurgents for resuming hostilities and said he was ready for a prolonged conflict.

"I told the soldiers to prepare for a long war. I said (peace) will not come during our generation," he said late Saturday.

He later threatened to jail rebel negotiators should they return from peace talks overseas.

"They are bandits... I do not think they are worthy of being called rebels. Plainly, they are terrorists," he said Sunday.

The government and the communists separately declared ceasefires in August, and the informal arrangement largely held as they continued discussions in Rome.

The president said he was now ordering government negotiators to "fold their tents and return home from the overseas talks.

"I am not interested in talking to them (the rebel leaders). I will refuse to talk about it anymore," he told reporters.

- Fifty years of fighting -

"We have been fighting for 50 years. If you want to extend it for another 50 years, so be it, we will be happy to accommodate you."

The rebels last week announced an end to their five-month-old ceasefire, accusing Duterte's government of treachery and human rights abuses.

The government responded by calling off its own unilateral ceasefire.

Duterte also denounced the 4,000-strong communist New People's Army for killing four soldiers in attacks last week, saying one of the victims had been riddled with 76 bullets.

Duterte's peace negotiators appeared hesitant in describing the volatile president's latest stance.

Government negotiator Jesus Dureza said in a statement, "he (Duterte) has clearly spoken on the directions we all in government should take. Let's take guidance from these recent declarations."

"The road to just and lasting peace is not easy to traverse. There are humps and bumps, and curbs and detours along the way. What is important is that we all stay the course," he said.

Chief communist peace negotiator Luis Jalandoni told ABS-CBN television on Sunday the rebels want talks to continue.

"The compelling reason is that the peace talks will try to achieve genuine peace based on justice, land reform, free distribution of land," he said.

"All of these things are still on the table and for the (communist leadership), it is worthwhile trying to continue the peace negotiations," he added.

He added that the NPA had killed the soldiers only "to defend themselves and defend the communities".

Duterte had previously made dramatic overtures to the communists, releasing some captured leaders so they could go abroad for peace talks and even appointing to his cabinet leftist figures named by the rebels.

The talks with the communists had appeared to be moving forward, with both sides describing the meeting in Rome last month as "successful."

But Duterte had refused communist demands to free hundreds of their jailed comrades.

The insurgency in the poverty-stricken country, which began in 1968, is one of the longest running in the world and has claimed an estimated 30,000 lives, according to the military.