Lax security in Mindanao State University could have led to the bombing of a Catholic Mass inside the campus last Sunday, a senior National Security Council official said.

NSC Assistant Director General Jonathan Malaya said that after the bombing, they received spot reports from the Philippine National Police that text messages of a possible attack were being circulated among the population.

Remnants of the Maute group, which conducted the five-month Siege of Marawi in 2017, are also active in the area, he said.

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"I think there was a lapse of security in the MSU campus itself. I am not entirely privy to the security arrangements of the campus itself but obviously there was lack of security measures that were implemented by MSU management," he said in an ANC Dateline Philippines interview.

He added: "Our suggestion to the Mindanao State University, in particular the Marawi campus, is to coordinate closely with the Philippine National Police and the Armed Forces of the Philippines moving forward. I think definitely security could have been heightened, more security measures could have been implemented, which could have prevented this attack."

He said the special arrangement allowing MSU to provide security for its own community has to end "because of the threat of violent extremism."

The Islamic State on Monday claimed responsibility for the blast that killed at least four people and injured at least 50 others. On its Telegram channels, the ISIS said "soldiers of the caliphate detonated an explosive device on a large gathering of Christians... in the city of Marawi."

• Islamic State claims responsibility for Mass bombing in Marawi

The NSC official, however, said there have been times that the Islamic State claimed responsibility for attacks, which later turned out to be false.

The Armed Forces of the Philippines meanwhile said it is investigating two persons of interest in the December 3 bombing.

AFP spokesman Col Medel Aguilar did not disclose the identities of the individuals, but stressed that they were being actively pursued by authorities.

• AFP identifies 2 persons of interest in Marawi bombing