PNP spokesperson Col. Allen Rae Co said the country's more than 40,000 public schools and around 6,000 private schools make such a deployment impossible.

"Hindi talaga natin kaya pong lagyan ang lahat ng schools. There are more than 40,000 public schools and around 6,000 private schools all over the country. Kahit lagyan natin ng tig-iisa lang ay wala nang magagawa ang ating kapulisan," Co said during a Palace briefing.

Instead, Co said the PNP is implementing strategic deployments and relying on support from local governments, barangay officials and force multipliers such as village watchmen.

"What we are doing is strategic deployment, when and where we are most needed. Kaya humihingi kami ng tulong at suporta ng local community, ng LGU at lalung-lalo na ng barangay," he said.

The PNP earlier deployed around 55,000 police personnel and force multipliers nationwide during the opening of classes this month.

Meanwhile, investigators are still determining how the firearms used in the attack were brought into the school.

Authorities confirmed that the 9mm pistol used in the shooting belongs to the aunt of one of the suspects, a police officer who has voluntarily submitted herself to an investigation.

Co said the police officer could face administrative sanctions, dismissal from service or criminal liability depending on the outcome of the probe.

Investigators are also tracing ownership of the .38-caliber revolver allegedly linked to a security guard.

The PNP is likewise verifying the authenticity of text messages allegedly exchanged by the two minors involved in the shooting, identified only as "Nash," 14, and "Rod," 15.

According to Co, initial findings indicate that one of the suspects was heavily influenced by online content.

"We can only say that based on our initial investigation, especially this CICL known as Nash, he was heavily influenced by online content," Co said.

Police are also examining the significance of KMFDM shirts reportedly worn by the two minors.

KMFDM is a German industrial rock band whose merchandise has, in some cases, been associated with school shooters seeking to emulate or reference the perpetrators of the 1999 Columbine High School massacre.

Co said investigators are studying whether the clothing has any relevance to the motive or planning of the attack.

The two minors are currently under the custody of the Department of Social Welfare and Development in accordance with the Juvenile Justice and Welfare Act.

Co also disclosed that the PNP supports proposals to lower the minimum age of criminal responsibility to 12 years old, citing police data showing an increase in crimes involving children in conflict with the law.

"As a matter of fact, we studied our data and statistics. Tumataas iyong nai-involve na mga CICL," he said.