Iran's Foreign Minister Mohammad Javad Zarif is set to visit China on Friday for talks on "regional and international issues", state news agency IRNA reported.
Coming amid soaring tensions between Washington and Tehran, the visit would be an opportunity to discuss the 2015 nuclear deal from which the United States unilaterally withdrew a year ago, IRNA said.
The China trip comes after Zarif visited Turkmenistan, India and Japan in the past week.
China is one of the five remaining parties to the Iran nuclear deal, in addition to Britain, France, Germany and Russia. It is also a major importer of Iranian crude oil and a permanent member of the UN Security Council with veto power.
In Tokyo, Zarif accused the United States of an "unacceptable" escalation of tensions and said Tehran was showing "maximum restraint" despite Washington's withdrawal from the nuclear deal.
Tensions were already high after President Donald Trump walked away from the accord in May 2018, but they have ratcheted up recently with the US deploying an aircraft carrier group and B-52 bombers to the Gulf over alleged threats from Iran.
Zarif said last week that only Russia and China had supported Iran and helped it keep the nuclear deal going, and accused other parties to the agreement of letting Tehran down.
In late April, Beijing said it "resolutely opposes" unilateral US sanctions against Iran that would bar it from purchasing Iranian crude.
China was one of the eight global buyers -- India, Turkey, Japan, South Korea, Taiwan, Italy and Greece -- that was allowed to import Iranian crude oil before the US ended waivers in early May.
Despite Washington's campaign of "maximum pressure" against Iran, the Islamic republic has vowed to keep selling oil to its main customers, especially China, even if it takes using indirect means.
On May 8, Rouhani said Iran would stop observing restrictions on stocks of enriched uranium and heavy water agreed under the nuclear deal in retaliation for the US withdrawal and the reimposition of sanctions.
In his announcement, Rouhani threatened to go further if the European members of the deal failed to start delivering on their promises to help Iran circumvent US sanctions within 60 days.
China in response called on all parties to uphold the nuclear deal in what it called a "shared responsibility".
European nations have also called on all partners to the deal to help salvage it while expressing frustration at Iran's demands for help solely from them to circumvent US sanctions.
One European diplomat called on China to buy Iranian oil as it is less exposed to the United States.
"They are now very exposed to the dollar but it is also a question of political choice," said the source who spoke on condition of anonymity.
"The reality for the Chinese is that they are in a global trade war with the Americans, they are in the middle of negotiations and they are not quite so sure if they want to load the boat," the diplomat added.