In what is seen as a crude imitation of the Iraq-based Islamic State (Isis), the al-Qaeda has released a video showing the group's own "Jihadi John" threatening two Western hostages in chilling English accent.

The Islamist, wearing a balaclava and military attire, speaks in fluent and clear English in the footage uploaded online.

The masked interrogator threatens the hostages, who were kidnapped by militants more than three years ago, in the video shot in the Sahara desert.

Though the 19-minute video, entitled "A Trip Interview Two Prisoners", cannot be independently verified, it closely resembles earlier videos produced by the al-Qaeda in North Africa (AQMI).

Directly looking at the camera, the Islamist militant says: "Welcome – to the world's largest prison. A prison that has no boundaries, a prison that has no walls, no cells, no bars."

"A prison with a fear, where prison break is non-existent. This is the mujahideen's prison, the Sahara."

The IS jihadist, who later became known as "Jihadi John", had earned a notorious reputation over his appearance in multiple execution videos showing chilling beheadings of prisoners.

The two hostages shown in the latest al-Qaeda video are thought to be South African Stephen Malcolm McGowan, who reportedly holds a British passport as well, and Swede Johan Gustafsson. They were abducted during an Islamist raid in Timbuktu in 2011 which also killed a German national.

Neither the location nor the exact date of the recording is clear.

Both the hostages are seen appealing to their respective governments for their release.

Gustafsson says: "I plead to the Swedish government that they are giving their help and information and support to my family and that they are doing what they can."

McGowan: "I have a message for my government: I want to thank you for everything that you have been doing and I continue to ask for help that you assist in my release."

The highlight of the al-Qaeda video is the use of sophisticated video editing techniques including sound-effects in likely replication of IS propaganda videos.

Another significant feature is the use of an English-speaking militant in predominantly Arabic and French Western Sahara.