Members of the Moro extremist group Abu Sayyaf clashed with government troops in Unkaya Pukan town in Basilan province on Friday, wounding at least 18 soldiers.
Capt. Maria Rowena Muyuela, military spokesman in Western Mindanao region in the southern Philippines, said there were also "undetermined casualties" on the enemy side in the ongoing fighting.
The hostilities came two weeks after the government entered into a final peace deal with the rebel Moro Islamic Liberation Front (MILF).
Friday’s clashes began just past 2am between troops of the Army's 104th Brigade, which was conducting "combat operations" against the forces of Abu Sayyaf leader Furuji Indama.
Muyuela said the operation was coordinated with the "ad hoc joint action group" of the MILF and the government.
She said the military campaign was meant to pursue “lawless elements," primarily Abu Sayyaf fighters who were believed to be behind abductions in Mindanao.
"The [military] will commit all available air and naval assets in support of this operation," she said.
The Abu Sayyaf this week have demanded US$11.25 million in ransom for a Chinese tourist abducted from a Malaysian dive resort on April 2, along with a Filipino resort worker.
The abductors are believed to be under the command of Abu Sayyaf "sub-commander" Murphy Ambang Ladjia, who was involved in the kidnapping of 21 people from another Sabah diving resort in 2000.
