LONDON: Qatar has asked US regulators to investigate the US subsidiary of the largest bank in the United Arab Emirates, accusing it of “bogus” foreign exchange deals designed to harm its economy as part of a blockade by Gulf neighbours.

The Central Bank of Qatar’s law firm has written a letter to the US Treasury asking it to investigate NBAD Americas, the US subsidiary of First Abu Dhabi Bank (FAB), which is majority state-owned.

In a second letter, the lawyers - Paul, Weiss, Rifkind, Wharton & Garrison - asked the US Commodity Futures Trading Commission (CFTC) to investigate possible manipulation of Qatar’s currency, the riyal.

The request for an investigation deepens the diplomatic crisis that erupted in June when Saudi Arabia, Egypt, the United Arab Emirates (UAE) and Bahrain imposed an economic boycott on Qatar, accusing it of supporting Islamist militants and Iran.

“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,” said the letter to the US Treasury dated Feb. 26, which has been seen by Reuters.

“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 said.

FAB, which was created from the merger of First Gulf Bank and National Bank of Abu Dhabi last year, did not respond to questions about details of the allegations.—Reuters