There has been no delivery of S400 systems to India and so the possibility of sanctions was not discussed, Austin told reporters in New Delhi on Saturday.
Washington blacklisted seven entities and two individuals in sanctions related to the Islamic Republic of Iran Shipping Lines and Iranian shipping entities.
The Treasury said in a statement it imposed sanctions on Luna Al Shibl, Assad's top press officer, and Mohamad Ammar Saati bin Mohamad Nawzad.
The United States and its allies are united in continuing to apply pressure on Assad and his enablers until there is peaceful, political solution to the conflict.