MANILA (UPDATED) - Malacañang on Monday condemned Abu Sayyaf's beheading of one of its captives, as the terrorist group grapples with intensified military offensives and the loss of one of its leaders during a foiled attack in popular tourist destination Bohol.

The military earlier said Noel Esconde, a boat captain, had been executed in the jungle near the town of Patikul on Thursday but his remains have yet to be recovered.

Esconde was abducted by the Abu Sayyaf along with three crewmen in December, while on board a fishing vessel in the Celebes Sea.

“We strongly condemn this senseless and coldblooded murder committed during the Holy Week. Local authorities and our security forces are exhausting all means to locate the captain’s remains, as our troops continue to pursue this bandit group and hold them accountable for their crimes,” presidential spokesperson Ernesto Abella said in a statement.

“We call on all citizens throughout the archipelago to remain vigilant, alert and watchful, and to cooperate with our security forces. Let us work against common criminals to make our communities safer and ensure a nation worthy of all Filipinos.”

Abu Sayyaf is a small but brutal militant group known for beheading, kidnapping, bombing and extortion in the south of the mainly Catholic country.

Brigadier General Cirilito Sobejana, commander of Joint Task Force Sulu, said it was likely the abductors beheaded Besconde because he was sick and had become a liability.

"The reason why he was beheaded is that he was delaying their movement," Sobejana told reporters. "They (Abu Sayyaf) are highly-mobile and we are pursuing them."

Sobejana said the group had demanded P3 million ($60,648.94) ransom for Besconde but the government maintained its policy of refusing to pay ransom.

The army has declared all-out war with Abu Sayyaf on the islands of Jolo and Basilan, but is hamstrung by its presence among large civilian communities.

Abu Sayyaf has its roots in separatism but its activities are mostly banditry and piracy and it has invested the profits of its business in modern weapons and fast boats.

Sobejana said the Abu Sayyaf group is still holding Besconde's crew, along with more than a dozen foreign nationals in Jolo.

The militant group last year beheaded Canadians John Ridsdel and Robert Hall. An elderly German, Jurgen Kantner, suffered the same fate in February when a $600,000 ransom demand was not paid.

The army said on Wednesday that an Abu Sayyaf leader, Muamar Askali alias Abu Rami, who was directly involved in the kidnap and execution of the Canadian and German nationals, was among those killed by Philippine troops in Bohol last week. – with Reuters