John Ridsdel
Canadian national John Ridsdel's neck was sliced with a machete BR10000/Twitter

Philippine militant group Abu Sayyaf has released a video showing the gruesome execution of Canadian hostage John Ridsdel. In a separate footage, the Islamic State-linked organisation threatened to carry out similar beheadings of three others if their demands were not met.

Ridsdel, 68, an oil executive, was beheaded on 25 April after the Canadian government refused to pay ransom to free him. The videos were obtained by the US-based SITE intelligence group, which monitors jihadist websites.

In the graphic video, four Islamist militants are seen standing behind Ridsdel with their index fingers raised. Then one of the jihaidsts slices through the victim's neck with a machete.

The Canadian's severed head was found by local government authorities after Abu Sayyaf's deadline expired.

Meanwhile, in the second video, the three other hostages — Canadian Robert Hall, Norwegian Kjartan Sekkingstad and Filipina Marites Flor — are seen pleading with their respective governments to pay the ransom.

Hall appealed: "To the Canadian government, I'm told to tell you to meet the demand. I don't know what you're doing, but you're not doing anything for us. John has been sacrificed, his family has been decimated, and I'm not sure why or what you're waiting for." Shortly after Ridsdel's execution, Canadian Prime Minister Justin Trudeau firmly ruled out paying ransom to terrorists to free the captives.

The other two captives in the latest video also said they would meet a similar fate as that of Ridsdel if their governments failed to act.

A masked captor, who appeared in the video, warned: "In the name of Allah, and all praise is due to Allah. Peace and blessings be upon the Messenger of Allah, and upon his family and his Companions. And thereafter: Note to the Philippine government and to the Canadian government: The lesson is clear. John Ridsdel has been beheaded. Now there are three remaining captives here. If you procrastinate once again the negotiations, we will behead this all anytime."

Abu Sayyaf, which primarily operates in the southern parts of the Philippines, is currently holding more than 10 hostages of different nationalities, including Japanese, Dutch and Malaysians.

Only on 1 May, the group had released 10 Indonesian sailors but there was no word about ransom payment.

Abu Sayyaf is a hardline militant group, also linked to al-Qaeda, which remains a serious security threat to the Manila administration and the Catholic-majority Philippines.