MANILA (Reuters) - A woman suspected of being a suicide bomber was killed in an explosion near a military detachment in the southern Philippines on Sunday, but there were no other casualties, the army said.

If confirmed, the incident would be the fourth suicide bombing in the restive southern Philippines in 14 months, adding to fears about the depth of Islamic State’s influence in the mainly Muslim region.

The military said troops on guard at the detachment in Indanan town in Sulu alerted fellow soldiers to take cover when a woman in Muslim attire was seen acting suspiciously. Moments later an explosion occurred.

The explosion could have caused heavy casualties, but for the actions of the troops guarding the detachment, regional task force commander Major General Corleto Vinluan said in a statement, adding that a detonator had been found at the scene.

There was no immediate claim of responsibility but the army suspects the Abu Sayyaf militant group to be responsible.

The Sulu archipelago is a stronghold of the Abu Sayyaf, a radical faction that has pledged allegiance to Islamic State. The group is notorious for piracy and kidnap for ransom.

Sunday’s incident came a day after an explosion at a public market elsewhere in the region wounded eight people.

Islamic State has claimed responsibility for the blast in a market in Sultan Kudarat province, but military investigators sought to downplay the militant group’s involvement. They suspect the attack was perpetrated by an “ISIS-inspired” group engaged in extortion.

Philippine President Rodrigo Duterte has vowed to wipe out Abu Sayyaf and has intensified military operations in its strongholds, though bombings targeting civilians and military have continued unabated.