At least three people have been killed and nine wounded after an explosion occurred during a mass in a university gymnasium in the southern Philippines, police said.
Authorities are investigating the explosion at Mindanao State University, a police spokesman said, adding that one angle being pursued was possible revenge by pro-Islamic State militants.
The blast happened in Marawi, a city besieged by Islamist militants for five months in 2017.
The Philippine military said they had killed 11 militants, including members of the Dawlah Islamiyah-Philippines, a pro-Islamic State group, in a military operation the day before in Maguindanao del Sur province.
"I condemn the violent bombing incident that transpired this morning," Lanao del Sur Governor Mamintal Adiong Jr said in a statement.
"Terroristic attacks on educational institutions must also be condemned because these are places that promote the culture of peace," he added.
Mindanao State University is "deeply saddened and appalled by the act of violence that occurred during a religious gathering," it said in a statement on Facebook.
"We unequivocally condemn in the strongest possible terms this senseless and horrific act," it said.
The university said it was suspending classes until further notice.
