The Islamic State in Iraq and Syria, also known as ISIS, IS, ISIL, or Da’esch, carried out its first major attack in the Philippines over the weekend in a 10-hour gun battle with the military in Basilan that killed at least 19 soldiers and 13 terrorists.

This was disclosed to Rappler by Rohan Gunaratna, the head of Singapore’s International Centre for Political Violence and Terrorism Research. “The group responsible is the Islamic State, led by Isnilon Hapilon in the Philippines,” Gunaratna told Rappler in a phone interview on Sunday, April 11. Gunaratna is the author of numerous books on security, including Inside Al-Qaeda.

“He’s the current leader of the Islamic State in the southern Philippines, and he has taken responsibility for this operation,” said Gunaratna.”So it’s wrong for anyone to say that this is a fight with the Abu Sayyaf because in Basilan, Isnilon Hapilon and all the other commanders have pledged allegiance to Abu Bakar al-Baghdadi (who leads ISIS). They are no longer loyal to Radullan Sahiron, the Abu Sayyaf leader.”