The US Treasury Department imposed sanctions on seven international companies based in China and Belgium on Thursday July 18th, saying it had taken action to shut them down.
In addition to this network of companies, the US also announced sanctions on five individuals over links to Iran’s nuclear programme.
"The treasury is taking action to shut down an Iranian nuclear procurement network that leverages front companies based in China and Belgium to acquire critical nuclear materials and benefit the regime's malign ambitions," Treasury Secretary Steven Mnuchin said in a statement.
"Iran cannot claim benign intent on the world stage while it purchases and stockpiles products for centrifuges," he added.
The sanctions imposed by the US are the first since Tehran announced earlier in July that it had amassed more low enriched uranium than allowed by the deal to which the European signatories are still committed together with Russia and China.