Philippine military says manhunt underway for bombing suspects

A "massive" manhunt is underway for the attackers who bombed a church service that killed four people in the southern Philippines, a senior military officer said on Monday, vowing to do everything possible to bring the perpetrators to justice.

Police are looking into at least two suspects they believe were behind the blast, which IS militants claimed.

"As we speak, there's an ongoing massive operation to hunt these terrorist groups or suspected perpetrators of the bombing," William Gonzales, Western Mindanao Command chief, told reporters after a security meeting in Marawi city.

The bomb went off on Sunday during a service at a university gymnasium in Marawi, a city left in ruins in 2017 by a five-month military campaign to end an occupation by IS loyalists that had triggered alarm across Asia.

"(We have persons) of interest, but the investigation is still ongoing. In order not to preempt the investigation, we will not divulge the names," regional police chief Allan Nobleza told GMA News, adding that one of the suspects was linked to a local militant group.

The United States condemned the "horrific terrorist attack" and said it stood with Filipinos in rejecting violence, joining a chorus of support from countries including Japan, Australia, Britain, China and Canada.

"We mourn those killed in the attack, and our thoughts are with the injured," State Department spokesperson Matthew Miller said in a statement.

IS militants claimed responsibility for the bombing at Mindanao State University, shortly after Philippine President Ferdinand Marcos Jr said "foreign terrorists" were responsible.

Military chief Romeo Brawner, who attended a security briefing with troops and police in Marawi, said he suspected the bombing could be a retaliatory attack for operations against local extremist groups in the southern region of Mindanao.

Spokesperson Xerxes Trinidad said the military was trying to validate the IS's claim of responsibility.

Of the 54 who were wounded in the bombing, Trinidad said only seven remained in hospital.

Classes resumed in Marawi on Monday, but with tighter security.