China's official Xinhua agency on Wednesday quoted Gong as telling reporters after meeting Iranian officials that China was willing to strengthen cooperation with all parties involved in the 2015 nuclear deal between Tehran and world powers, known as the Joint Comprehensive Plan of Action (JCPOA).
He added that the parties should use dialogue and negotiation to resolve the dispute.
In a speech from the White House on Tuesday, US President Donald Trump accused Iran of sponsoring terrorism and seeking nukes before announcing the US withdrawal from the nuclear deal.
Following the controversial decision, Iranian President Hassan Rouhani said Iran weighs plans to remain in the agreement with the other five parties, namely Russia, China, Britain, France and Germany, provided that the remaining JCPOA parties ensure its full benefits for Iran.