ISLAMIC State militants have claimed responsibility for Sunday’s bomb attack at the Mindanao State University (MSU) in Marawi City which killed four people and injured at least 50 others.

The IS said on Telegram its operators detonated the explosive while the victims were attending an early morning mass in the gymnasium of the university.

Marawi City was rocked by five-month fierce fighting between government forces and heavily-armed terrorists belonging to the IS-linked Maute and Abu Sayyaf Groups in 2017.

President Ferdinand R. Marcos Jr. condemned “the senseless and most heinous acts perpetrated by foreign terrorists” in the MSU gymnasium shortly after the bombing Sunday morning.

Bangsamoro Administrative Region-Police Regional Office director Brigadier Gen. Allan C. Nobleza said they have identified more than two ‘persons of interest’ in the bombing.

He said one of them is a suspected terrorist. He didn’t elaborate. The official said a Special Investigation Task Group has been created to spearhead the investigation into the case and hunt for the bombers.

As of press time, law enforcement operations are still ongoing to arrest all suspects behind the bomb attack. Defense Secretary Gilberto C. Teodoro Jr. said there were ‘strong indications of a foreign element’ in the bombing and added operations to get the terrorists to “continue unabated.”

Police and military bomb experts are also working to reconstruct the bomb used in the attack. Initially, officials said that the improvised explosive device is believed to have been fashioned out from a 60-mm mortar round.

Armed Forces chief of staff Gen. Romeo S. Brawner Jr. has aired the possibility that the MSU bombing was launched by the terrorists to ‘avenge’ the killing of 11 of their fellows during an Army offensive in Maguindanao del Sur the day before.

Lanao del Sur Governor Mamintal Adiong Jr. said the four fatalities in the bombing have been identified. The official said that 35 out of 47 people who were brought to the hospital following the explosion have been discharged after treatment.

Two others however were listed in critical condition and needed to undergo surgery.

The bombing, which happened around 7:00 a.m., took place just hours after Army troops killed 11 members of the Dawlah Islamiyah terror group in a gun battle in Brgy. Tuayan in Datu Hofer, Maguindanao Friday.

PNP chief Gen. Benjamin Acorda placed all Mindanao police units on full alert in the aftermath of the bombing.

PNP spokesperson Colonel Jean S. Fajardo also called on residents to provide them with relevant information that would result in the identification and arrest of the bombers.

“The PNP remains committed to prioritizing the safety and security of our citizens. We are determined to bring those responsible for this tragedy to justice and will provide the public with updates on any significant developments in the investigation,” she said.

Col. Fajardo said units from the PNP Special Action Force and the PNP Explosive and Ordnance Division (EOD)/K-9 Group have been deployed in Marawi City to conduct paneling activities in areas of convergence.