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."

CLICK HERE FOR MORE FROM THE SUN

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.

This frame grab from video posted online Friday, Jan. 18, 2019, by supporters of the Islamic State group, purports to show a gun-mounted Islamic State group vehicle firing at members of the U.S.-backed Syrian Democratic Forces, in the eastern Syrian province of Deir el-Zour, Syria.

This frame grab from video posted online Friday, Jan. 18, 2019, by supporters of the Islamic State group, purports to show a gun-mounted Islamic State group vehicle firing at members of the U.S.-backed Syrian Democratic Forces, in the eastern Syrian province of Deir el-Zour, Syria. (Militant Photo via AP)

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

TRUMP: ISIS COULD LOSE REMAINING TERRITORY WITHIN WEEK

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.

CLICK HERE FOR THE FOX NEWS APP

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