"Today's action targets Iran's revenue from the export of industrial metals -- 10 percent of its export economy -- and puts other nations on notice that allowing Iranian steel and other metals into your ports will no longer be tolerated,"

Tehran and Moscow have called on the European sides to the 2015 Iran nuclear deal to comply with their commitments to guarantee the survival of the agreement, officially known as the Joint Comprehensive Plan of Action (JCPOA).

"China will take an objective, fair and responsible attitude, keep communication and cooperation with all parties concerned, and continue to work to maintain the deal," Wang said.