Philippine President vows to neutralise Islamist militants who beheaded Canadian hostage

John Ridsdel was executed by Abu Sayyaf militants on Monday

Photo taken 27 May, 2000, shows Muslim Abu Sayyaf rebels holding Western hostages taking position outside the mosque in their stronghold in Jolo island (ROMEO GACAD/AFP/Getty Images)

The Philippine President has said "casualties are to be expected" as he vowed to devote all his energy to eliminating the Islamic militants who beheaded a Canadian hostage.

John Ridsdel, 68, was executed by Abu Sayyaf militants on Monday. He was captured along with three others in 2015 while on holiday in the Philippines.

His head, placed in a plastic bag, was dumped by motorcycle-riding gunmen in Jolo town in the southern province of Sulu, five hours after the expiry of a ransom deadline set by the militants.

John Ridsdel appears in his Twitter photo. (John Ridsdel/Twitter)

President Benigno Aquino III said in a statement: "So, to the ASG [Abu Sayyaf Group], and whoever may aid or abet them, you have chosen only the language of force, and we will speak to you only in that language.

"Casualties are to be expected. But what has to be of utmost importance is neutralising the criminal activities of the ASG."

Abu Sayyaf, which is linked to Isis, is believed to be holding 22 foreign hostages from six Western and Asian countries hostage.

The Philippine military and police said "there will be no letup" in the effort to combat the group and find the hostages.

Government troops have been ordered to carry out assaults without endangering the remaining hostages.

About 2,000 military personnel, backed by Bell UH-1 "Huey" and MG520 rocket-firing helicopters and artillery, are involved in the manhunt for the militants, who are believed to be massing in Sulu's mountainous Patikul town, military officials said.

Canadian Prime Minister Justin Trudeau has said his country and Britain will urge other nations not to pay ransoms to free kidnap victims.

Mr Trudeau said if Canada paid ransoms, it would put all of its all of its citizens who traveled or lived abroad at risk.

The Isis-linked Abu Sayyaf has collected tens of millions of dollars in ransoms since it was formed in the 1990s, security experts say.

While the Philippines rarely publicises payments of ransom, it is widely believed no captives are released without them.

Additional reporting by agencies