MANILA– President Rodrigo Duterte on Friday said he has decided to abandon peace negotiations with the National Democratic Front of the Philippines (NDFP), saying the fighting between government and communist rebels could go on for “another 50 years.”

Speaking to reporters in Davao City, Duterte said he is sensing that the NDFP was no longer interested in pursuing talks with the government given its continued criticism of some of his policies and the New People’s Army’s (NPA) relentless attacks on state troops.

“Actually… at this time, they have decided to stop talking. I’ve decided to just abandon the talks,” Duterte said in an chance interview in Davao City.

Duterte reiterated his vow to scrap talks with communist rebels after Communist Party of the Philippines (CPP) founding chairman Jose Maria Sison said it might be better to end talking peace with the Duterte government because of its “obsession with martial law and mass murder.”

“I believe you, Mr. Sison. You are right. We should stop talking,” Duterte said separately in a speech in Davao City, addressing his former professor.

“That was 50 years ago. Let us renew the fighting for another 50 years. Anyway, all of us will not see the light of day on this revolution of yours,” he said.

Duterte's decision came following a string of rebel attacks on government forces, including an ambush on his security men in Arakan, North Cotabato on Wednesday.

A militiaman was killed while 4 officers of the Presidential Security Group (PSG) were wounded in the incident.

• READ: Palace: NPA attacks 'fuel doubts' on Reds' sincerity in peace talks

The President also backed Solicitor General Jose Calida’s move to seek the arrest of NDFP consultants temporarily freed to take part in the peace talks.

Government had released on conditional pardon 20 leftist leaders held on various crimes, including theft and multiple murder, so they could take part in the negotiations.

“They have to surrender or we will hunt them down. Please do not resist or magkagulo tayo nyan. Do not resist,” he said.

Saying he is willing to wage a war with the rebels until his 6-year term ends, Duterte told Sison to let communist rebels “sacrifice”.

“Karamihan naman ng mga sundalo mo mahirap, taga bukid…Let them die. I can fight for another 50 years. Let us agree on that, and let us be as ferocious as each other. No quarters given, no quarters asked,” he said.

Duterte decided to scrap talks with the NDFP in the wake of recent NPA attacks against state troops.

• READ: Duterte says no more talks with communist rebels

Ending the decades-old communist insurgency had been a top priority for Duterte, but talks went on and off under the feisty leader, who accused the communists of being two-faced because of their persistent armed attacks against government forces.

Friction between Duterte and communist leaders recently escalated when the President placed the entire Mindanao under martial law to address the terror threat posed by Islamic State-linked terrorists, who have laid siege on Marawi City.

Duterte said putting the region under martial law was a painful but necessary decision that he had to make, even if the communists were against it.

“Unfortunately, when I was Mayor, you come to me, I go to you and we can talk because I was just a Mayor. Ngayon, pasensya na lang. I really have to break your friendship because I now handle the affairs of the nation,” Duterte said in his speech.

“And just to remind you, itong mga walang utak na duwag [na nagsasabing] martial law will create dictatorship, if I want to be a dictator, all I have to do is to be in good graces with the military. All I have to do is promote them to general,” he said.

He also slammed the NDFP and the Communist Party of the Philippines for supposedly branding him a “bully.”

“I bully people who try to topple government and all the enemies of the state. That is my job-- to bully you and to kill you-- because there is a war going on between us and you. You are killing my soldiers, my policemen so I bully you,” he said.

The President has also lambasted the rebels for collecting “revolutionary taxes” from businesses and ordinary people.

On Wednesday, government announced it had canceled supposed backchannel talks with the NDFP this week due to the persistent NPA attacks.