Senator Ronald "Bato" dela Rosa on Monday floated the possibility that failure of intelligence may have played a part in the deadly bombing at the Mindanao State University in Marawi City on Sunday which killed at least four people and injured 50 others.

"The failure of intelligence is possible because they failed to monitor it. If they were able to monitor it, it could be a failure to act on intelligence," said Dela Rosa, a former Philippine National Police chief.

However, he stressed that it would be "very unfair" for government security forces if he would conduct an investigation against them into the supposed lapses.

"It would be very unfair for our security forces if we made them accountable due to the supposed failure of intelligence," Dela Rosa said. "If they did not monitor anything, it means it was below their radar."

When asked about potential backlash from the public due to the security forces' failure to gather intelligence about the attack despite having confidential and intelligence funds, Dela Rosa said, "People will be asking for accountability."