US slaps sanctions on Iran shipping network over 'Syria oil smuggling'

The US imposed tough new sanctions on an Iranian shipping network on Wednesday, it accused of being run by the Revolutionary Guards and selling millions of barrels of oil to benefit Syria's Bashar al-Assad.

The sanctions on 16 entities, 10 people and 11 vessels were announced just as Iran was threatening to cut further its commitments under a nuclear deal unless Washington eases economic pressure on Tehran.

The Treasury Department said that the Quds Force, a unit of the elite Revolutionary Guards responsible for external operations, had backed both Assad and its Lebanese ally Hezbollah through crude oil shipments, mostly to Syria. 

"The Iranian regime is leveraging a terrorist organization as its chief conduit for obfuscating and selling hundreds of millions of dollars of illicit oil to fuel its nefarious agenda," said Sigal Mandelker, the under secretary of the treasury for terrorism and financial intelligence.

The State Department said separately that it was offering a $15 million reward for information that can disrupt the financial mechanisms of the Revolutionary Guards, including the Quds Force.

The entities that are facing the new sanctions include the Mehdi Group, based in US ally India, and its director Ali Zaheer Mehdi, which the Treasury Department said has managed vessels for Iranian oil.

On Tuesday, an Iranian oil tanker previously held by the UK turned off its tracking beacon amid increasing suspision the vessel is heading to Syria, despite assurances from Tehran that it would not.

The former Grace 1 was detained off the coast of Gibraltar by the UK navy in early July on suspicion of heading towards Tartous to offload oil in contravention of European Union sanctions on the Syrian regime.

Gibraltar authorities ultimately released the Iranian oil tanker last month, despite repeated US requests to seize the tanker. It claimed the tanker is controlled by the Iranian Revolutionary Guard, which it classifies as a terrorist organisation. 

Tensions between arch-enemies Iran and the US have soared ever since Washington stepped up its campaign of "maximum pressure" against Tehran and reimposed sanctions after leaving the landmark 2015 nuclear deal last year.

President Donald Trump in June called off at the last minute an airstrike on Iran over its downing of a US spy drone, amid a military and naval buildup by Washington and its ally the UK in the Gulf.

Iran has also captured several oil tankers off its coast in the past months, reportedly in retaliation for the seizure of the former Grace 1.