Militants have killed five Filipino soldiers and wounded 23 others in a major ambush by members of a notorious Islamist kidnap-for-ransom group, the Philippine military said Saturday.
The soldiers were searching for hostages taken by the Abu Sayyaf group when the gunmen attacked them on the southern Philippine island of Jolo on Friday, regional military spokesman Lieutenant Colonel Gerry Besana told reporters.
"The effort is part of our mission to rescue the remaining hostages," Besana said.
The Abu Sayyaf is a loose alliance of several hundred armed militants formed in the 1990s with seed money from Osama bin Laden's Al-Qaeda network.
Friday's clash was one of the deadliest since an Abu Sayyaf faction joined other foreign and Filipino militants in seizing the southern Philippine city of Marawi last year, leading to a five-month battle that claimed more than 1,100 lives.
The Abu Sayyaf is now believed to hold "less than 10" hostages, Besana said.
The group is based in the strife-torn southern islands but its members began in 2016 to kidnap sailors in the waters between Indonesia, Malaysia and the Philippines.
The militants have also raided and taken hostages from resorts in the southern Philippines and neighbouring Malaysia.
Most of the hostages have been ransomed off for huge amounts of money and several were beheaded, including two Canadian tourists in 2016. A Dutch birdwatcher abducted on a nearby island in 2012 is believed to be among those still in Abu Sayyaf's hands.
The Dutchman's Swiss colleague escaped in 2014 after grabbing a kidnapper's machete and killing him.
The soldiers who survived Friday's ambush did not see any hostages during the 90-minute clash near the town of Patikul, Besana said.