At least 20 people have been killed in two bombings at a Roman Catholic cathedral in the Philippines.

One bomb exploded inside the cathedral on the southern island of Jolo while the second went off outside the main doors as people rushed in to help.

Police said jihadists of the Abu Sayyaf group were the main suspects.

President Rodrigo Duterte's spokesman called the attackers godless criminals who were trying to "sow chaos".