The USA put two Chinese individuals and six organizations on a black list because they had some affairs with Iranian shipping company, and even assisted them with avoidance of sanctions imposed by the US.
Consequently, all the active resources of these organizations and private parties were frozen and deals with the US individuals are strongly restricted.
The US Secretary of State says that if people want to have business with this Iranian shipping company, they may be subject to sanctions by the USA.
Moreover, these six organizations supplied shipping sector of Iran with some important goods and services.
These sanctions were imposed by the United States in 2018 in order to reject nuclear deal which Iran established with six large countries in 2015.
The aim of this agreement was not to allow Iran to get nuclear weapon. Tehran made a decision to restrict its nuclear affairs with Iran to be relieved from economic sanctions in return.
However, the president of the USA states that the deal of 2015 didn’t restrict nuclear activities of Iran and, thus, Tehran will have to make a more substantial deal. However, Iran doesn’t admit that it tends to possess nuclear weapon.