Clouds of paper bills fill the air as a building in Islamic State's Iraq stronghold is flattened by two 2,000lb bombs.

The aerial footage, released by the US Defence Department, shows a building being targeted in Mosul - the extremist group's main stronghold in Iraq.

Clouds of paper bills quickly fill the air as the building is flattened by two 2,000-pound bombs.

The Pentagon said several millions of dollars in cash were destroyed, but the exact amount is not known.

The US-led coalition has been targeting IS oil resources and cash piles in the hope of sapping its financial strength.

IS earns an estimated £315m ($450m) a year from oil production in its territory in Iraq and Syria.

The terror group also has a small army of tax collectors raking in nearly as much from zakat tax, a form of almsgiving in Islam, according to the Financial Times.

Zakat requires Muslims to hand over part of their income - and can be given to those who are fighting for a holy cause.

IS takes 2.5% of capital from wealthy residents and businesses, 5% of irrigated crops and 10% of rain-fed crops from farmers.

The result is hundreds of millions of dollars in revenue each year, the FT said.

It even collected £16m ($23m) in taxes on salaries the Iraqi government paid to officials in Mosul after the city was taken over by IS.

Source: Sky News