US treasury is nothing more than a 'jail warden', tweets Iran's Javad Zarif

The US treasury is nothing more than a "jail warden", Iranian Foreign Minister Mohammad Javad Zarif tweeted on Thursday, a day after Washington imposed fresh sanctions designed to choke off the smuggling of Iranian oil.

"OFAC (Office of Foreign Assets Control of US Treasury) is nothing more than a JAIL WARDEN: Ask for reprieve (waiver), get thrown in solitary for the audacity. Ask again and you might end up in the gallows," Zarif wrote on his Twitter account.

The tweet came a day after US imposed sanctions on a shipping network it said was run by Iran's Revolutionary Guards, saying it sold millions of barrels of oil to benefit Syrian President 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 the United States eases its pressure.

The Treasury Department said that the Qods 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 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 Qods 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.