They are not ISIS they are just attention seeker they want to get the attention of international group called "ISIS" to have fund to their activities they are the Maute groups the one who plant a bomb on night market davao hoping that after the declaration president duterte will force all his trops to kills those animals who killed 9 christians already.
They are ISIS inspired group. I remember I put up a thread about this Maute group in the Philippines a few months back. I think they are trying hard to be recognized by ISIS. They attacked Marawi City, but the latest news says that the terrorist is now fleeing but it will take days to be cleared because snipers are present and IED's along the way. I don't know but the timing of the attack coincides with the Manchester bomber so I don't know if this is a coordinated attack. Even President Duterte cut his Russian Trip short to go back to Manila and personally see what is going on. I'm sure he is so pissed right now that he want to shot this terrorist.