Metro Manila (CNN Philippines) — Elements of the Philippine Army seized Monday the "last stronghold" of the Abu Sayyaf group in Tipo-Tipo, Basilan in their ongoing operations against the bandits in Mindanao, an Army lieutenant said Tuesday.

Lieut. Ron Villarosa, Public Affairs Officer of the 4th Special Forces Battalion, told CNN Philippines the ASG suffered some casualties, as the military launched the operations against the Abu Sayyaf's bastion of power called Hill 355 at Barangay Silangkum at high noon on Monday.

"The hill is the ASG's last stronghold after the terrorists went on the run from the relentless military operation that started last July," Villarosa said in his Facebook post.

He also said some soldiers were injured in the operations.

Maj. Filemon Tan, spokesman for the military's Western Mindanao Command (Wesmincom), said the ASG camp has 10 enemy bunkers that can be occupied by at least seven people, four tunnels spacious enough for 20 people, several foxholes for eight people, a kitchen hut and an exit post. Authorities also recovered two improvised explosive devices (IEDs).

Tan said intelligence reports show since July, around 45 ASG members have been killed in military operations.

Last Sunday, the military seized two other strategic strongholds of the ASG located in Barangay Baguindan Proper and nearby Hill 440 (Kawilan Hill) in Tipo-Tipo.

Tan said troops from the Special Forces, Scout Rangers, elite Counterterrorism Units, and Light Armored Cavalry forced ASG fighters out of their camps -- which had seven foxholes and 12 bunkers capable of accommodating at least 80 ASG fighters.

Government troops also recovered three unexploded ordnances and several IEDs.

The Special Forces said the successful operation is a "liberation" for residents of Baguindan, Tipo-Tipo and Bohe Piang of Al-Barka, areas affected by the presence of ASG fighters.

Prior to the attacks, elements of the Philippine Army conducted several dialogues with the residents around the area, including members of the Moro National Liberation Front (MNLF), Villarosa said.

Also read: MNLF backs 'all-out war' against Abu Sayyaf

"We were working with the MNLF and the other civilians from the area and we were fortunate enough to have a glimpse of the local terrain," Villarosa said.

Tan earlier said there was lack of cooperation from residents. He said then relatives of Abu Sayyaf members might even be providing sanctuary to fleeing bandits.

But now, Villarosa said some residents "have grown tired" of ASGs seeking refuge in their areas.

"We've seen an increase, a very dramatic increase in their cooperation with the government troops," Villarosa said.

The ASG has gained notoriety for ransom kidnappings, beheading hostages and bombings. Their latest victims were two Canadian hostages who were beheaded after no ransom was paid to spare their lives.

Read: Who are the Abu Sayyaf?

President Rodrigo Duterte said there will soon be a "day of reckoning" with the Abu Sayyaf and promised to dismantle the group.

Following the president's directive, Armed Forces of the Philippines (AFP) Chief Lt. Gen. Ricardo Visaya vowed there will be unrelenting military operations against the ASG in July.

Related: PH gov't condemns ‘brutal and senseless’ murder of ASG hostage