The latest suspected ISIS propaganda film has been uploaded to YouTube and appears to feature a jihadist with an American accent.

The 55-minute 'Flames of War' video was posted online today and bears hallmarks of previous Islamic State tapes including Hollywood-style effects and bloodthirsty, call-to-arms language.

The clip bears the stamp of the al-Hayat Media Centre, ISIS' English-language propaganda arm.

WARNING: GRAPHIC CONTENT

An ISIS jihadist spoke with an American accent on the Flames of War propaganda film which was uploaded to YouTube today. In the video, the masked extremist stands before Syrian soldiers, loyal to dictator Bashar al-Assad who are digging their own shallow grave outside the city of Raqqa

A male voice in well-spoken English with a non-specific American accent provides the voice-over, using dialogue seemingly hijacked from a blockbuster action film.

He says: 'In the face of the dark wave of the crusader force, the historical land of two rivers bore life to a mission that would transform the political landscape of the world.'

Almost an hour follows of battle scenes where militants wield rocket launchers, the footage manipulated with special effects. Piles of bloodied corpses are spliced with speeches by President Obama and former president George W Bush.

The tape builds to shaky camera footage of the extremists' raid on the 17th Division air force base in Raqqa, Syria under the cover of darkness.

In the final minutes of the tape, a masked jihadist in desert fatigues, speaks directly to camera in a different American accent to the man who provided the voice-over.

An ISIS flag billows as Syrian soldiers, loyal to dictator Bashar al-Assad, dig their own shallow shallow graves in the sand.

In a deep voice, the ISIS militant, who appears tall and well-built, speaks first in Arabic before transitioning into fluent, well-spoken English to deliver a chilling message.

He said: 'We're here in the 17th division military base just outside the city of Raqqa.

In the chilling tape released on Friday, ISIS line up the Syrian soldiers captured during an attack on an airbase in Raqqa

In the sickening footage, the soldiers are shot in the back of the head by the ISIS militants, their bodies rolling into a shallow grave

'We're here with the soldiers of Bashar, you can see them now digging their own graves where they were stationed. The very place they were stationed, terrorizing the Muslims in Raqqa.

He goes on to say that the work of Allah will be carried out on the soldiers by the mujahideen who captured them.

'This is the end that they face,' he said, gesturing to the men digging in the sand.

The tape then cuts to a captured soldier holding a shovel in a pit who says: 'Today we're digging our graves with our own hands... Our fate is to be slaughtered.'

He said that ISIS with just a few dozen soldiers were able to take over the 800-strong Syrian army base.

The tape ends with the American-accented jihadist brandishing a handgun and saying: 'The fighting has just begun.'

A line of masked ISIS militants then shoot the kneeling soldiers in the back of their heads, the bodies pitching forward into a mass shallow grave.

HOW MANY AMERICANS ARE WITH ISIS? FBI 'INVESTIGATING 40' As many as 40 Americans have returned to the U.S. after fighting for the ISIS terror army overseas and are under investigation by the FBI. Democratic Rep. Tim Bishop made the remarks during a speech to Long Island Metro Business Action on September 12. 'One of the concerns is the number of U.S. citizens who have left our country to go join up with ISIS,' he said. 'It is believed there have been some number up to 100 that have done that.' 'It is also believed that some 40 of those who left this country to join up with ISIS have now returned to our country. Those 40 are under FBI attention and surveillance. So they are known and they are being tracked by the FBI.' American jihadis, part of a swelling 'foreign fighter' contingent aiding the self-designated Islamic State of Iraq and al-Sham (ISIS) could put their ideologies and experience to work in the United States, a fact that has some in Congress clamoring for easier ways to revoke their citizenship. The Pentagon said two weeks ago that only about a dozen Americans had left the country to join up with ISIS, while as many as 100 are suspected of taking up arms with a wider range of Islamist extremist groups in the Middle East and Africa. DAVID MARTOSKO Advertisement

MailOnline is not running the full video.

The U.S. State Department had yet to comment on Friday when contacted by MailOnline about the authenticity of the tape and the suspected involvement of an American.

Just days ago, ISIS had released a similarly slickly-produced 'Flames of War' trailer warning the U.S. of the carnage it wants to inflict in Iraq if President Obama deploys troops to the war-torn nation as he attempts to 'degrade and ultimately destroy' the terror group.

Timing of the trailer and the feature-length film, suggested ISIS were directly responding to General Martin Dempsey, the chairman of the Joint Chiefs of Staff, who told the Senate Armed Services Committee this week that fighting in Iraq may require the use of ground troops.

The trailer was also released by the al-Hayat Media Center, which has become known for its propaganda videos for ISIS which include high-production values, CGI explosions and slow motion footage.

The movie is just the latest heavily-edited video from ISIS that has included gruesome footage of the beheadings of two American journalists and a British aid worker.

In the latest hostage video released on Thursday, British photojournalist John Cantile sits behind a desk and in a measured tone makes the case for Western powers to negotiate with his captors.

His appearance is very similar to that of fellow British hostages Alan Henning and David Haines, who were seen in a video released by ISIS earlier this month.

The footage taken of the other hostages, including American journalists James Foley and Steven Sotloff, was characterised by the masked figure of 'Jihadi John'.

He - and his weapons - are absent from the video of Mr Cantile.