Qatar has asked the US to investigate reports that the American subsidiary of the largest bank in the UAE is manipulating the Qatari currency. 

Qatar has asked the US to investigate reports that the American subsidiary of the largest bank in the UAE is manipulating the Qatari currency to harm the country's economy amid a diplomatic dispute with Saudi Arabia. 

The Central Bank of Qatar has sent a letter to the US Treasury, urging it to investigate NBAD Americas, the US subsidiary of the largely state-owned First Abu Dhabi Bank (FAB).

"We believe NBAD has participated in an extraordinary and unlawful scheme to wage financial warfare against Qatar, including through the manipulation of Qatari currency and securities markets," Reuters quoted the letter as saying.

"These actions should be halted immediately, and we ask that you investigate whether NBAD has directly or indirectly supported the manipulation of Qatar's markets, including through NBAD America's dollar-clearing or correspondent banking services in the United States," the letter added.

In a second letter, the Qatari central bank's international law firm Paul, Weiss, Rifkind, Wharton & Garrison asked the US Commodity Futures Trading Commission (CFTC) to probe possible manipulation of the Qatari riyal.

"NBAD's quotes - and those of other banks involved in the manipulation - were likely all bogus," the letter to the Treasury said.

“There is evidence that at the same time NBAD was providing quotes with great frequency and at rates lower than the official rate of 3.64, its traders were unwilling to actually transact at those prices,” it said. 

The United Arab Emirates (UAE), Saudi Arabia, Bahrain and Egypt all cut off diplomatic ties with Qatar and imposed a trade and diplomatic embargo on the emirate in June last year, after officially accusing it of “sponsoring terrorism”.

Doha strongly denies the allegation.

The Saudi-led bloc presented the emirate with a list of demands, among them downgrading ties with Iran, and gave it an ultimatum to comply with them or face consequences.

Doha refused to meet the demands and said that they were meant to force the country to surrender its sovereignty.

Amid the diplomatic crisis, Abu Dhabi has taken an especially tough line towards Doha.

Last month, Qatar’s Defense Minister Khalid bin Mohammad al-Attiyah said Saudi Arabia and the UAE had planned a military invasion of his country at the beginning of a diplomatic crisis that erupted last year.

A series of leaked documents revealed in November 2017 that the UAE had a stunning detailed plot to launch an economic war on Qatar.