MANILA (Reuters) - Philippine soldiers arrested on Monday a communist rebel leader, days after President Rodrigo Duterte scrapped a ceasefire with the insurgents and as clashes between them and the army erupted in several places.

Duterte announced on Friday the government was scrapping the ceasefire with the New People’s Army (NPA) and he ordered soldiers to prepare to fight, saying the rebels were making “huge”, unacceptable demands despite government concessions.

The rebel leader arrested on Monday, Ariel Arbitrario, was among dozens of guerrillas freed last year when the government and the rebels resumed peace talks.

He was intercepted at an army checkpoint in Davao City, in the southern Philippines, a military spokesman said.

“He was taken in based on President Duterte’s pronouncement to re-arrest all those who were freed temporarily to take part in the peace talks,” the spokesman, Captain Rhyan Batchar, told reporters.

“He and a companion will be brought back to prison.”

The conflict between the government and the NPA, the armed wing of the Communist Party of the Philippines, began in 1969 and more than 40,000 people have been killed.

Duterte, who won an election last year on a vow to wipe out the illegal drug trade, had raised hopes of bringing an end to a communist insurgency that has stunted development for years, especially in central parts of the Philippines.

Last month, the government asked the U.S. State Department to remove the rebel movement’s founder and leader, Jose Ma. Sison, from its terrorist blacklist to move negotiations forward.

But both sides later traded accusations of truce violations and negotiating in bad faith.

“Let’s go to war,” Duterte said in a speech on Monday, calling rebels “spoiled brats” demanding too much from the government. He now calls the NPAs as a terrorist group.

Another military spokesman said there was a spike in skirmishes between the army and the rebels in central and southern parts of the country over the past 48 hours. Three other rebels were captured and one was killed in one clash, said military spokesman Colonel Edgard Arevalo.

Separately on Sunday, soldiers killed a guerrilla in a 30-minute firefight on the central island of Mindoro while skirmishes also occurred in Iloilo and Masbate, also in the central Philippines, Arevalo said.

At the peak of the Maoist rebellion, there were 25,000 NPA fighters but its strength has fallen to about 3,000 members. The army said the rebels are concentrated in the country’s eastern seaboard where there are many plantations and mines, main sources of rebel funding.