Iranian Revolutionary Guards
Iranian Revolutionary GuardsReuters

An Iranian airliner was sold a commercial jet for use in aiding Syrian dictator Bashar al-Assad, in breach of the terms of the nuclear deal signed earlier this year.

Mahan Air, one of Iran's largest domestic and international carriers, purchased the UK-made aircraft specifically for use in ferrying Iranian Revolutionary Guard troops to and from Syria, where they and other Iranian-sponsored militias are propping up the embattled Assad regime, according to International Business Times.

Mahan Air has long been used by Tehran to transport arms and military forces to Syria. The sale of the aircraft was a blatant breach of sanctions still in place under the terms of the Joint Comprehensive Plan of Action, or JCPOA, as the nuclear deal is referred to.

Speaking at a 2011 press briefing in Washington, D.C., US under secretary for terrorism and financial intelligence David Cohen described how "Mahan Air’s close coordination with the Quds Force - secretly ferrying operatives, weapons and funds on its flights - reveals yet another facet of the Islamic Revolutionary Guard Corps' extensive infiltration of Iran’s commercial sector to facilitate its support for terrorism."

That same year the US slapped sanctions on the company, accusing it of using its planes to ferry an assassin who planned to kill Saudi Arabia's ambassador to the US.

"Temporary sanctions relief... currently in place does not cover the sale or lease of complete aircraft to Iran," Betsy Bourassa, a representative of the Office of Terrorism and Financial Intelligence within the Treasury Department in Washington told IBT.

"This could affect the way Iranian sanctions are eased," one legal expert said, noting such a flagrant violation could have an impact on the implementation of the deal - if, that is, the Obama administration doesn't turn a blind eye to it.

Aviation records reportedly show that Mahan purchased the jet from one A. Grundlingh on Oct. 15. A man by the name of Anton Grundlingh registered the plane in South Africa, where he is the director of three aircraft-affiliated companies and a shareholder in a financial-services firm, according to IBI.