(2nd UPDATE) The explosion occurs while a group, mainly students, gather for a Mass at the Mindanao State University's Dimaporo Gym

COTABATO, Philippines – At least four people were killed while at least 42 others were hurt as an explosion ripped through a gym at the state-run Mindanao State University (MSU) in Marawi City during a Mass on Sunday morning, December 3, according to Jenny Tamano, Lanao del Sur provincial government spokesperson, who released an update regarding the casualty count.