MANILA - Philippine President Rodrigo Duterte on Monday (Jan 28) ordered security forces to crush a band of Muslim militants suspected of perpetrating a twin bomb attack on a Roman Catholic cathedral in the volatile south that left at least 20 dead and over 100 wounded.
Security officials tagged six "persons of interest" from the Ajang-ajang faction of the Abu Sayyaf as the main suspects.
The Abu Sayyaf has pledged allegiance to the Islamic State in Iraq and Syria (ISIS), which claimed responsibility for the attack.
When asked what Mr Duterte wanted the military and the police to do, Defence Secretary Delfin Lorenzana told reporters: "On the Abu Sayyaf, crush them (for the bombings) and for all the atrocities they have committed so far."
Mr Lorenzana accompanied Mr Duterte during a brief visit to Jolo town in Sulu province, where the militants set off two blasts that tore through the Cathedral of Our Lady of Mount Carmel during mass on early Sunday morning.
A senior military official said the Ajang-ajang faction was formed in 2014 and consists of no more than 60 kin - mostly teenagers - of Abu Sayyaf militants killed over the years by security forces.
Ajang-ajang is an ethnic term in Sulu that means "sons of warriors" or "sons of martyrs".
The military official, who asked not to be named because he was disclosing sensitive information, said the faction had never ventured out of Jolo island, and mostly stuck to extortion, drug dealing and spotting hostages for the Abu Sayyaf.
Mr Rommel Banlaoi, executive director of the Philippine Institution for Peace, Violence and Terrorism Research, told CNN Philippines that the group had apparently levelled up to ideology-fuelled revenge killings.
He named Hatib Sawadjaan, an ISIS sympathiser and father-in-law of Malaysian militant Amin Baco, as among the leaders of the Ajang-ajang faction.
Baco was at one time rumoured to have been designated as the new ISIS emir in South-east Asia, replacing Isnilon Hapilon, the Abu Sayyaf chieftain killed in the 2017 siege of southern Marawi city.
The church attack came nearly a week after more than 1.5 million Muslims in the predominantly Catholic nation overwhelmingly approved a more powerful autonomous region in the south.
They voted for the new region called Bangsamoro, or nation of Moros, in hopes of ending nearly five decades of separatist rebellion and reining in a new wave of Islamist extremism sweeping war-torn Mindanao island.
Voters in Sulu, however, rejected it. Still, the province will be included in the new region, as it is part of the Autonomous Region in Muslim Mindanao, which as a bloc voted overwhelmingly in favour of the Bangsamoro law.
That has raised fears of reprisals by militant groups, who are opposed to any peace deal with the government and opting instead to embrace ISIS' wider agenda to establish a caliphate in South-east Asia.
The country's 170,000-strong police force are now on "heightened alert status". This means more checkpoints and patrols, especially around shopping malls, train and bus stations, airports, harbours and other vulnerable targets.