Four people have been killed and several others are wounded after an explosion ripped through a Catholic mass in the southern Philippines on Sunday, Report informs via ABC News.

Authorities are investigating the explosion, which took place in a university gymnasium at Mindanao State University, regional police director Brigadier General Allan Nobleza said.

Among the dead were three women and 50 others were brought to two hospitals for treatment of mostly minor injuries, officials said.

Allan Nobleza added police would investigate whether the explosion was a possible revenge by pro-Islamic State militants, and whether a homemade bomb or grenade was responsible.

The blast occurred in Marawi, a city besieged by Islamist militants in for five months in 2017.

The Philippine military said on Saturday they had killed 11 militants, including members of the pro-Islamic group Dawlah Islamiyah-Philippines in a military operation on Friday in the Maguindanao del Sur province.