Militants have threatened to kill three more hostages in their jungle base in the southern Philippines more than a week after beheading a Canadian man when their multimillion-dollar ransom demands were not met.

In a video circulated Tuesday by the Site Intelligence Group, which monitors jihadi websites, the captives from Canada, Norway and the Philippines pleaded for the Canadian and Philippine governments to heed the Abu Sayyaf militants’ demand.

Six heavily armed Abu Sayyaf fighters stood behind the hostages, who were made to sit in a clearing and spoke briefly before a camera. A black flag hung amid a backdrop of banana trees and lush foliage.

Norwegian hostage Kjartan Sekkingstad said that if the kidnappers’ demand was not met, “we will be executed like our friend John”.

The militants beheaded John Ridsdel on 25 April in the southern Philippine province of Sulu, an impoverished Muslim province in the south of the largely Roman Catholic country, after they failed to get a ransom of 300 million pesos ($6.3m, £4.3m).

Justin Trudeau, the Canadian prime minister, condemned the killing but vowed not to give in to the kidnappers’ ransom demands. Following the beheading, the Philippine military launched an offensive, which security officials believe has killed more than a dozen gunmen so far.

Canadian captive Robert Hall asked the Philippine government to “please stop shooting at us and trying to kill us. They’re gonna do a good job at that.” He asked his government to heed the militants’ demand.

Holding back tears, Filipino Marites Flor asked several officials and prominent Philippine personalities, including local presidential candidates, for help “because we want to be freed alive”.

A masked militant warned Canada and the Philippines that the three remaining hostages would be killed “if you procrastinate once again”.

It was the first time the three captives had been shown in a video after Ridsdel’s killing.

The four were seized from a marina on southern Samal Island and taken by boat to Sulu, where Abu Sayyaf gunmen continue to hold several captives, including a Dutch birdwatcher who was kidnapped more than three years ago, and eight Indonesian and Malaysian crewmen who were snatched recently from three tugboats.

The militants freed 10 Indonesian tugboat crewmen a few days ago, reportedly in exchange for ransom.

The US and the Philippines have separately blacklisted the Abu Sayyaf for kidnappings for ransom, beheadings and bombings. The brutal group emerged in the early 1990s as an extremist offshoot of a decades-long Muslim separatist rebellion in the south.