The sick terror group will activate hundreds of sleeper cells in "dozens of countries" in an unprecedented bid to destabilise western governments.

The shock claim, from one of the world's leading authorities on the death cult, comes amid fears of a New Year's Eve terror plot in London and other major world cities.

ISIS has carried out more than 50 attacks in 18 countries that have killed 1,100 people and injured 1,700 since it declared in 2014.

And next year will see a huge increase in both the number and scale of major terror attacks, according to Dr Theodore Karasik, a Gulf-based analyst of regional geo-political affairs who has extensively studied ISIS's behaviour.

He warned: "ISIS’s media operation is taunting its enemy to come to fight their Final Battle.

"But first, it wants to show its global reach with zeal...from cells, to lone wolves, to target landmarks and crowds in dozens of countries across the world."

Dr Karasik added: "There are close to 40 ISIS affiliates globally with millions of adherents and believers around the world. The New Year may ring in with disturbing terror attacks.

"ISIS is an airborne disease and still remains robust as the movement enters into a new combative and aggressive phase.

"Many of us see the change of year as 'turning over a new leaf' and ISIS may do the same.

"The level of ISIS’s destructiveness, to force confrontations across the world, indicates that 2016 is likely to be more chaotic than 2015.

"The threat is real, and the requirement for international, regional, and local cooperation is truly necessary and will be tested again and again in perhaps unexpected places."

The warnings come as the west is on heightened alert after last month's terror attacks in Paris, in which 130 people were killed and hundreds wounded.

Earlier this week ISIS leader Abu Bakr al-Baghdadi released an audio message boasting that his forces were "doing well" and urging his followers to "be confident God will grant us victory".

Dr Karasik believes Baghdadi will now accelerate his campaign of terror.

He added: "He is following the script announced in 2014 to expand in the Levant into the upper tier of the Arabian Peninsula by 2019.

"ISIS still run rampant and firmly believe in their stated goals.

"Baghdadi taunts America and its allies who are afraid to put boots on the ground against ISIS to fight because of what waits in Dabiq and Ghouta, which is a reference to what the leader describes as the Final Battle.

"This type of language plays well with ISIS’ audience, wherever they may be." he continued.

The Takfiri ISIS terrorist group has reportedly executed many civilians in Iraq and Syria, Express reported.

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