It says nine marines were injured and six others were missing after a clash near Tipo Tipo town on Basilan island.

Tuesday's clash took place as the army searched for a seized Italian priest.

The kidnappers are believed to be either Abu Sayyaf militants or the Moro Liberation Front, seeking an independent state in the south.

Marine spokesman Lt Col Ariel Caculitan said the marines ran into a group of some 300 armed men during their search for the priest, triggering the clash.