Two companies linked to a Chinese state-owned oil company and a pair of Cosco Shipping Energy Transportation subsidiaries have been slapped with sanctions by the US after alleged dealings with Iran.

Among others, Kunlun Shipping Company, Kunlun Holding Company, Cosco Shipping Tanker (Dalian) and Cosco Shipping Tanker (Dalian) Seamen and Ship Management were added to the US Treasury Department's specially designated nationals list Wednesday.