MANILA, Dec 25 (Reuters) - A crude bomb exploded on Saturday in the roof of a Roman Catholic church at a police base on a Muslim-dominated southern island in the Philippines wounding six people, an army spokesman said.
The Catholic priest celebrating the early morning Christmas mass was among those wounded, said military spokesman Lieutenant-Colonel Randolf Cabangbang.
Cabangbang said about 100 people were at the service in the main police base on the island of Jolo, a stronghold of the Abu Sayyaf, a small Islamist militant group with ties to al Qaeda.
"We've placed our troops on alert to prevent similar attacks on churches, shopping malls, parks and transport terminals," Cabangbang said.
No group claimed responsibility for the attack. The Abu Sayyaf has been blamed for several bomb attacks on the Roman Catholic cathedral in Jolo since the early 2000s and for kidnapping priests and nuns.
Dozens of U.S. army Special Forces have been deployed on Jolo since 2004 to help train and advise security forces fighting the militants. (Reporting by Manny Mogato; Editing by Robert Birsel)