Communist guerillas killed six Philippine soldiers and wounded six others on Tuesday, the military said, in one of the deadliest recent attacks in the country's 50-year-old Maoist insurgency.
Members of the New People's Army (NPA) detonated bombs in a pre-dawn ambush of soldiers marching through a mountainous area of central Samar island, triggering a four-hour firefight.
"Our troops had received a report that NPA forces were extorting money from residents and so they went there to take action," said regional military spokesman Captain Reynaldo Aragones.
Rebel casualties had not been determined, but Colonel Ramon Zagala confirmed the soldiers' deaths to AFP.
The 4,000-strong NPA, the armed wing of the Communist Party of the Philippines, has waged a guerrilla campaign that has killed up to 40,000 people since 1969.
It marked the 50th anniversary of its founding in March with an assault on a police station that killed three rebels and wounded two police officers.
NPA units rarely engage large military units in big firefights, preferring to target poorly equipped provincial police forces or isolated military or paramilitary detachments.
Tuesday's attack was among the deadliest launched by the NPA since mid-2017, when President Rodrigo Duterte called off peace talks with the now 50-year-old insurgency.
That decision followed a series of NPA attacks that killed six police officers and wounded five of the president's military bodyguards.
Decades of peace efforts have come to naught, despite a burst of optimism when Duterte was elected.
Talks with his government seemed to initially make progress, but then fell apart amid name-calling and threats from both sides.
Various attempts to revive the peace process have continued despite Duterte declaring the effort finished in 2017.
Duterte branded the talks dead yet again last month, saying the communists "can maybe talk to the next president of this republic one day".