ISIS chiefs have stashed away millions to fund a new wave of attacks against Britain and the West - as the terror group faces being stamped out once and for all.

U.N. experts believe the group has around $300 million stored in "bulk" - with one report warning it will be used to fund "larger-scale attacks once the opportunity arises."

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The warning comes as ISIS face being finally routed in Syria as fighters supported by British and U.S. special forces close in for the kill.

On Monday, Kurdish-led coalition forces battled to clear the village of Baghouz, where the remaining jihadis are holed up in fortified positions.

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But the operation was slowed by landmines and sniper fire as fighters desperately battled to hold off the onslaught.

A U.N. Security Council report into the threat posed by ISIS warned the group still has up to 18,000 armed terrorists ready to fight to the death.

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This story originally appeared in The Sun. For more from The Sun, click here.