The Abu Sayyaf Group kidnapped the four people in a resort in Davao in September 2015. (Source: calgarysun.com)

Hanoi (VNA) - Islamic gunmen in the southern Philippines issued a new warning on May 4, threatening to kill three hostages just over a week after they beheaded a Canadian captive.

The hostages - from Canada, Norway and the Philippines - appealed for help from the Philippine and Canadian governments in a video uploaded to YouTube on the same day.

The video showed them sitting on the ground, beneath what appeared to be a coconut plantation, with six gunmen standing behind them.

One of the gunmen then warned Manila to learn the lesson of Ridsdel's killing and avoid delays in negotiations.

Philippine President Benigno Aquino has vowed to neutralise the gunmen and his government has said it will not negotiate with a group it considers a terrorist organisation.

Aquino said the three hostages were being held on the Abu Sayyaf stronghold of Jolo island, more than 1,000 kilometres south of Manila.

The gunmen believed to be member of the Abu Sayyaf Group kidnapped the four people in a resort in Davao in September 2015.-VNA