A bombing attack carried out by Islamic State forces killed four people and injured dozens at a university in the Philippines on Sunday.

The blast ripped through the gymnasium of the Mindanao State University in Marawi City on Mindanao island - a predominantly Muslim region - where a Catholic mass service was being held on December 3 morning.

Harrowing footage shows panicked locals carrying injured people out of the building, where blood was splattered on the concrete floor. Plastic chairs were overturned by the blast with burnt debris and glass littering the gymnasium floor.

Police said at least four people were killed and at least 50 were injured.

The Philippine National Police said fragments of a 60mm mortar were found at the scene, and investigations were ongoing to find who had planted the explosive.

The Islamic State (IS) has claimed responsibility for the bombing, saying on its Telegram channels that 'soldiers of the caliphate detonated an explosive device on a large gathering of Christians' in Marawi City.

Defense Secretary Gilbert Teodoro Jr. said in a press conference: 'There are strong indications of a foreign element. Let's leave it at that so the investigation by both the Philippine National Police and Armed Forces of the Philippines will not be hampered.'

Authorities said it was possible the bombing was carried out in retaliation for a recent series of military operations targetting pro-IS Islamist extremist groups in Mindanao.

Philippine President Ferdinand Marcos Jr, son of the country's former dictator Ferdinand Marcos and wife Imelda, said in a statement: 'I condemn in the strongest possible terms the senselss and most heinous acts perpetrated by foreign terrorists upon the Mindanao State University (MSU) and Marawi communities early this Sunday morning. Extremists who wield violence against the innocent will always be regarded as enemies to our society.'

Marawi is the Philippines' largest Muslim city. It was previously captured by Islamist militants in May 2017, with more than a thousand killed before being liberated five months later by the Philippine military.