The measures cover Greek national Antonios Margaritis and his network of companies and vessels that the treasury said were involved in transporting Iranian oil exports in violation of sanctions.

Treasury also designated Ares Shipping Ltd in Hong Kong, Comford Management in the Marshall Islands and Hong Kong Hangshun Shipping Ltd in Hong Kong.

Designated crude oil tankers include Panama-flagged vessels Adeline G and Kongm, and Lafit under the flag of Sao Tome and Principe.

The state department separately said it imposed sanctions on two China-based operators of oil-related terminals and storage.

It said they handled imports of Iranian oil aboard tankers previously targeted by US sanctions.

The firms were identified as Qingdao Port Haiye Dongjiakou Oil Products Co in Shandong province and Yangshan Shengang International Petroleum Storage and Transportation Co in Zhejiang province.

A person at Qingdao Port Haiye Dongjiakou Oil Products Co who answered a phone call told Reuters they were not aware of the sanction and declined to comment.

State-owned Qingdao Port International, the major shareholder of Haiye, did not respond to a request for comment.

Yangshan Shengang International Petroleum Storage and Transportation did not immediately respond to a request for comment.

Iran suspended talks with Washington aimed at curbing the Islamic Republic’s nuclear ambitions after the US and Israel struck its nuclear sites in June.

Iran denies any intent to develop atomic bombs.

Iran’s top diplomat said on Wednesday that the moment for “effective” nuclear talks with the US has not yet arrived, adding that Iran would not completely cut off cooperation with the UN nuclear watchdog.