Metro Manila (CNN Philippines) — The New People's Army (NPA) on Wednesday said it is terminating the unilateral ceasefire it declared last year.

"The August 28 unilateral ceasefire shall effectively expire on 11:59 p.m. of February 10," Ka Oris, NPA spokesperson, announced in a statement. NPA is the armed wing of the Communist Party of the Philippines (CPP) which has waged a 48-year-old insurgency.

The NPA cited two reasons for deciding to end its five-month old ceasefire declaration.

"Una, nabigo ang rehimeng Duterte na tuparin ang pangakong palayain ang lahat ng bilanggong pulitikal kahit matapos ang halos 160 days mula nang pinagusapan ito nung Agosto (First, the Duterte regime failed to fulfill its promise to free all political prisoners, 160 days since it was discussed in August)" Ka Oris said in a video published by the CPP Information Bureau's official Facebook page.

The NPA said they declared an interim ceasefire on August 28 "on the mutual understanding" with the government that political prisoners will be released within 60 days.

The rebels extended the ceasefire, but the Duterte regime still failed to fulfill its obligation, the NPA said.

The NPA also said the government "has treacherously taken advantage" of the ceasefire and attacked the rebels' territories.

Skirmishes among NPA fighters and military troops have been reported even after a unilateral ceasefire was both declared by the government and the rebels.

The NPA said government troops occupied at least 500 barrios that served as home to the rebels. Soldiers threatened and harassed the people, the NPA said.

It also claimed eight soldiers and an NPA fighter were killed in a firefight in Makilala. North Cotabato on January 21. The Army has recently denied there were casualties from the clash, but communist rebels formally submitted a letter to the government peace panel protesting the alleged military operation in Makilala as a violation of the ongoing ceasefire.

'Negotiate while fighting'

The NPA said it will continue to support the peace talks between the government and the National Democratic of the Philippines (NDF), which represents the rebels in the negotiations.

The panels failed to sign a bilateral ceasefire agreement after the third round of peace talks in Rome, Italy last January, but they agreed to discuss it on February 22-27 in the Netherlands. The fourth round of peace talks has also been scheduled to resume in Oslo, Norway on April 2-6.

Also read: GPH-NDF talks in Rome 'most important'

"In our experience and in the experience of other peoples, it is possible to negotiate while fighting until the substantive agreements are forged to address the roots of the armed conflict and lay the basis for a just and lasting peace," the NPA said.

The NPA ordered all of its commands and units to continue to "carry out active defense in order to defend the people and revolutionary forces."

It issued a stern warning that the rebels will "counteract, frustrate, and punish" government forces.

Gov't ceasefire holds

Despite the NPA's withdrawal of its truce declaration, the government's unilateral ceasefire declaration remains, Presidential Spokesman Ernesto Abella said.

"The Department of National Defense will continue to observe the government's unilateral ceasefire, at the same time enforce the campaign to protect civilians from harm and terrorism," Abella said in a statement on Wednesday.

Defense Secretary Delfin Lorenzana promised that government "troops will not actively operate against the NPA while our ceasefire is in effect."

He, however, accused the rebels of conducting attacks against soldiers and civilians even when their ceasefire was still in place.

Although Presidential Peace Adviser Jesus Dureza expressed "dismay" over the latest setback to the peace process, he said the government peace panel remains committed to its search for lasting peace.

"We are still hopeful that the search for peace will continue and the tragedy of Filipinos fighting fellow Filipinos will come to an early end," Dureza said in a statement.

Abella said President Rodrigo Duterte "will continue to exercise strong political will to move forward with the peace talks with the CPP-NPA-NDF."

CPP founding leader Jose Maria Sison earlier said a final peace deal can only be signed by 2020-2021, after the government releases all political prisoners, and addresses other rebel concerns.