The Islamic State's 'emir of suicide bombers' raised a staggering $2million for 'military operations' from a mystery Qatari donor, U.S. officials have said.

Tunisian-born Tariq bin al-Tahar al-Harzi, 32, one of the terror group's most senior commanders, allegedly arranged to receive the funds from a Gulf-based 'financial facilitator'.

The unnamed donor told him the cash must be used for 'military operations' and also enlisted the terrorist's help with 'fundraising efforts in Qatar', according to the U.S. Treasury.

The revelations have sparked calls for the Gulf state, the richest per capita in the world, to prevent its citizens from aiding the flow of funds to Syria-based terror groups, such as ISIS.

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Terrorist: Tunisian-born Tariq bin al-Tahar al-Harzi (pictured), 32, the Islamic State's 'emir of suicide bombers', has raised a staggering $2million for 'military operations' from a mystery Qatari donor, say U.S. officials

Calls for action: The revelations have sparked calls for the Gulf state, the richest per capita in the world, to prevent its citizens from aiding the flow of funds to terror groups like ISIS. Above, Qatar's capital, Doha

But despite increasing criticism, Qatar, which has an extensive London property portfolio including luxury department store Harrods, is now 'working together' with the U.S. against ISIS.

The Gulf has contributed two Mirage jet fighters to President Barack Obama's air campaign against militants, which are being controlled from a headquarters outside Qatar’s capital, Doha.

Al-Harzi, who is believed to be one of ISIS's first ever terrorists, is among a number of jihadists to be recently added to the Treasury's list of Specially Designated Global Terrorists.

Other named jihadists include a middleman between al-Qaeda’s leadership in Pakistan and Gulf financiers and another ISIS senior commander who is believed to oversee a prison where foreign hostages are held.

Accused: Tarkhan Batirashvili (left) allegedly oversaw an ISIS prison facility in al-Tabqa, close to al-Raqqah, where foreign hostages were held, while Amru al-Absi (right) is reportedly the group's 'kidnapper-in-chief;'

Militants: Al-Harzi, believed to be one of ISIS's first ever terrorists, is among 11 jihadists and one terrorist group newly added to the Treasury's list of Specially Designated Global Terrorists. Above, ISIS militants in Syria

In addition to 'raising funds', Al-Harzi allegedly serves as ISIS's 'emir' of the border region between Turkey and Syria and works to 'recruit and facilitate the travel of fighters' for the terror group.

In this capacity, he has reportedly received 'new foreign fighter recruits and provided them light weapons training before sending them to Syria'.

He has also 'facilitated the movement of Europeans to Turkey' (including fighters from the UK, Albania and Denmark), organised suicide attacks in Iraq and helped ISIS to develop its fighters' abilities to build car bombs and improvised explosive devices, the Treasury said.

British MP Stephen Barclay said the allegations against al-Harzi's - in particular, the $2million he has reportedly raised - underlined the need for Qatar to 'clamp down' on the flow of money to ISIS.

Property portfolio: Despite the calls for action, Qatar, which has an extensive London property portfolio including Harrods (pictured), is now 'working together' with the U.S. against ISIS (also known as ISIL or IS)

'These further revelations underline the need for Qatar to demonstrate clearly its commitment to clamping down on the clear flow of money that has helped to facilitate the grip of Isil,' the Conservative MP told The Telegraph, using another name for the group.

'Specifically, there needs to be action against those who have been complicit or directly involved in delivering this funding.'

These revelations underline the need for Qatar to demonstrate clearly its commitment to clamping down on the clear flow of money that has helped ISIS British MP Stephen Barclay

Daniel Byman, of the Brookings Institute, added that the country had 'not put significant barriers in the way' of such monetary transfers.

'A lot of people believe the government has, in fact, allowed it to happen,' he said.

Among the other jihadists named as 'global terrorists' by the Treasury was Tarkhan Batirashvili, who has reportedly held a number of top military positions within ISIS.

Known as 'Omar the Chechen', Batirashvili allegedly oversees an ISIS prison facility in al-Tabqa, close to al-Raqqah, where foreign hostages may be held.

In late 2013, he led around 1,000 foreign fighters to attack the Syrian regime at Jabal Shuwayhnah in Rif Aleppo, Syria, said the Treasury.

Abd al-Aziz al-Fadhill, a Kuwait-based facilitator who allegedly provides support to al-Nusra Front, was also named in the Treasury's list, released on Wednesday.

He has reportedly co-ordinated the transfer of 'hundreds of thousands of dollars' to the terrorist group, as well as facilitating travel for individuals seeking to join it.

President: The Gulf has contributed two Mirage jet fighters to President Barack Obama's (pictured) air campaign against militants, which are being controlled from a headquarters outside Qatar’s capital, Doha

Meanwhile, Ibrahim al-Bakr, 37, has been listed as a key link between al-Qaeda's leadership in Pakistan and financiers in the Gulf.

He is 'responsible for collecting money for both al-Qaida and the Taliban', as well as playing a 'key role in a terrorist cell that was plotting to attack U.S. military bases and personnel in Qatar'.

Other jihadists named by the Treasury include Ashraf al-Salam, Umar al-Qatari, Fatih Hasar, Hamad al-Shammari, and Bambang Sukirno, as well as the terrorist group Hilal Indonesia.

It comes as the British Parliament has voted to approve the UK's participation in U.S.-led airstrikes against ISIS.

Prime Minister: It comes as the British Parliament has voted to participate in U.S.-led airstrikes against ISIS. David Cameron (pictured) told members of Parliament that the group was plotting terrorist attacks in Britain

Six RAF Tornados were expected to join US, French and Arab air strikes – their first in Iraq for six years – today after MPs voted overwhelmingly to go into a third Gulf War.

Warning that the fight to crush IS could last for years, not months, David Cameron told an emergency session of Parliament that as well as murdering Western hostages with ‘staggering brutality’ the group was plotting terrorist attacks in Britain.

‘This is about psychopathic terrorists trying to kill us,’ the Prime Minister said. ‘We do have to realise that whether we like it or not, they have already declared war on us.’