Acting Sulu provincial Gov. Kadil Estino says the bombing late Saturday was carried out by the militant Abu Sayyaf group in retaliation for the killing of a member by the military in a clash three days earlier.

Police Chief Glenn Roy Gabor in the provincial capital, Jolo, says the bomb was placed in front of a grocery store that is a favorite shopping place for Philippine marines.

The shop was closed and most of the victims were bystanders in a nearby park.

The Abu Sayyaf is on Washington’s list of terrorist groups and has been blamed for numerous kidnappings, beheadings and bombings.