Al Shabaab video threat
The masked militant is heard speaking in a strong British accent.YouTube

A video has been released by Islamist militants calling for radicalised Muslims to carry out terrorist attacks on some of the busiest shopping areas in the UK and US.

The 77 minute footage was released by the al Shabaab group, the Somali-based affiliate of al-Qaida on Saturday (February 21).

According to The Guardian, the video features a black man in a military style jacket, with his face covered by a headscarf, urging followers to carry out attacks on "American and Jewish-owned" shopping centres.

Speaking in a strong British accent, he says: "We call upon our Muslim brothers, particularly those in the west, to answer the call of Allah and target the disbelievers wherever they are."

Referring to the 2013 attack on the Westgate mall in Kenya he says: "If just a handful of mujahedeen fighters can bring Kenya to a complete standstill for nearly a week, imagine what a dedicate mujahed in the West could do to American or Jewish owned shopping centres across the world?

"What if such an attack on the Mall of America in Minnesota or the West Edmonton mall in Canada or in London's Oxford Street. Or any of the hundred or so of the Jewish owned Westfield shopping centres. Take the Westfield shopping centre in Stratford or White City for example, what would be the implications of such an attack, one can only imagine.

"'All it takes is a man with firm determination, of which our Muslim ummah (community) has plenty of."

After mentioning Oxford Street as a potential target, he gives GPS coordinates for the Westfield shopping centres in Stratford and Shepherd's Bush.

Several shopping malls in the US are also mentioned as prime targets for the attackers with the Mall of America in Minnesota, highlighted. Another target is the West Edmonton Mall in Alberta, Canada, is the largest shopping mall in North America.

He finished his speech with the chilling message: "So hurry up and hasten to Heaven and do not hesitate."

westgate shopping mall siege nairobi al shabaab
Al Shabaab have threatened more attacks like the 2013 bombing of the Westgate shopping mall in Nairobi (Reuters)

Jeh Johnson, the chief of homeland security in the US, said the threats are being taken seriously.

"Anytime a terrorist organisation calls for an attack on a specific place, we've got to take that seriously," he said. "I would say that if anyone is planning to go to the Mall of America today, they've got to be particularly careful.

"This latest statement from al Shabaab reflects the new phase we've evolved to in the global terrorist threat, in that you have groups such as al Shabaab and ISIL publicly calling for independent actors in their homelands to carry out attacks."

In a statement a spokeswoman for the Mall of America confirmed officials are aware of the video and had implemented extra security measures as a precaution.

"We will continue to monitor events with the help of federal, state and local law enforcement agencies," said the statement. "As always, we take any potential threat seriously and respond appropriately."

The Somali-based militants have previously claimed responsibility for the 2013 attack on an upmarket shopping mall in Kenya by four gunmen, which left 67 people dead and more than 175 wounded.

The Metropolitan Police's Counter Terrorism Command is assessing the content of the video.