At least 15 people were killed after around 25 gunmen detonated bombs and attacked fleeing civilians on a southern Philippine island.
Reports said the military claimed that Islamic militants from the Abu Sayyaf group were responsible for the attacks on Basilan Island.
Isabela city mayor Cherry Akbar told reporters that of the 15 people confirmed dead, five were militants apparently killed by one of their own bomb blasts. Six civilians were killed in the blasts, with three soldiers and one policemen killed in gun battles following the attacks.
Many of the armed men were wearing police and military uniforms, officials said.
Reports earlier said that three Philippine Marines and a policeman were killed when the gunmen ambushed them as they rushed to the capital Isabela city, after the first of two bombs exploded, regional army spokesman Lieutenant Steffani Cacho told AFP.
AFP also reported that militants fired on civilians running to safety, engaging in a viscious gun battle with troops and police that lasted for three hours.
Cacho said the first bomb tore through a van parked near a sports grandstand and a government office in Isabela city. A second bomb rigged to a motorcycle damaged a Catholic church nearby.
"It heavily damaged the church," Senior Superintendent Antonio Medoza told AFP.
"The men were shooting at civilians as they fled towards a forested area," he added.
No one has claimed responsibility for the attacks, but several armed Muslim groups operate in Basilan, including the al-Qaeda-linked Abu Sayyaf.
Over the last couple of months, several attacks on Basilan and neighbouring Jolo Island have injured dozens of soldiers - US and Filipino - as well as civilians.