Iranian Foreign Minister Abbas Araghchi was visiting China on Wednesday for consultations ahead of a new round of nuclear talks with the United States.
Iran and the United States are set to meet in Oman on Saturday for a third set of talks on the Iranian nuclear issue, with Araghchi and US Middle East envoy Steve Witkoff leading the negotiations.
A technical meeting between nuclear experts from the two countries will also be held on Saturday in the Omani capital, Muscat.
"It is necessary for us to keep our friends in China informed of developments and to consult with them," Araghchi told Iranian state television.
China was a party to the 2015 nuclear agreement that reined in Tehran's nuclear programme, which was abandoned after US President Donald Trump withdrew from it three years later.
"China has played an important and constructive role on the nuclear issue in the past, and the same role is certainly necessary in the future," the Iranian minister added.
The 2015 agreement provided for the lifting of international sanctions against Iran in exchange for oversight of its nuclear program by the International Atomic Energy Agency (IAEA).
According to the IAEA, Iran was complying with its commitments until the US withdrawal, which triggered the reimposition of US sanctions.
The 2015 accord, formally known as the Joint Comprehensive Plan of Action (JCPOA), was also negotiated by four other permanent UN Security Council members -- Britain, France, Russia, and the United States -- along with Germany and the European Union.
China is Iran's largest commercial partner and the main buyer of its oil, with Tehran still under crushing US sanctions.
Around 92 percent of Iranian oil heads towards China, according to Iranian media, and is often sold at a considerable discount.
In 2021, Tehran and Beijing signed a comprehensive 25-year strategic agreement covering energy, security, infrastructure and communications among other areas.