Leaders of the Philippine Roman Catholic Church, Asia's largest, have vowed to counter extremist religions such as that espoused by Islamic State militants in Syria and Iraq.

Archbishop Socrates Villegas, who heads the country's Catholic bishops, also asked churches on Thursday to collect donations for Christians who have been displaced by the militants and whose places of worship have been razed "by a godless rage with which no genuine religion can ever identify."

Citing actions by the Islamic State group including the beheading of American journalist James Foley, Villegas said the Philippine church would "do our part ... to counter the defacement of religion."

Militants belonging to the Abu Sayyaf and another violent Muslim group in the southern Philippines have expressed support for the Islamic State group.