"Despite developments at the regional and international level, Beijing's determination for maintaining friendly relations with Tehran will not change," Song Tao, the head of International Liaison Department of the Communist Party of China, said in a meeting with First Vice President Es'haq Jahangiri in Tehran.
Jahangiri said top Iranian officials have placed expansion of relations with China on their agenda, IRNA reported.
Song pointed to challenges facing oil and energy collaborations, hoping that the two countries would soon find ways of addressing the problems and expedite the implementation of their joint projects, Financial Tribune reported.
China is Iran's major trade partner and oil customer, but has faced restrictions due to the United States sanctions on Tehran.
"Despite the knowledge of restrictions faced by friendly countries such as China, we expect them to work more actively toward purchasing Iranian oil," Jahangiri told the Chinese diplomat.
He also called for the launch of a mutual financial mechanism to facilitate trade between the two countries.
A delegation of experts from the Central Bank of Iran and the Economy Ministry is expected to travel to China in the coming week, according to Jahangiri, to work on the details of such a payment channel.
Song also expressed his country's willingness to develop tourism ties between the two countries, saying Beijing's government would support its Chinese nationals' visit to Iran.
Iran welcomes cooperation in this sector and has waived visa requirement for Chinese tourists on a 21-day visit.
Citing the pressure exerted on both countries by the United States, Song said Tehran and Beijing need to exchange views on how to take proper approaches to solve their problems and protect their shared interests.
China has been engaged in a trade war with the US through increasing tariffs and other measures since 2018. Iran is also under harsh sanctions that Washington reimposed after withdrawing from the 2015 nuclear deal, formally known as the Joint Comprehensive Plan of Action, last year.
"The two countries can share their experiences on how to combat the US pressure," Song said.
Iran has initiated a reciprocal plan to gradually scale down its commitments under the deal. It has declared, however, that all the moves would be reversed as soon as the remaining parties successfully meet its concerns.
"China understands Iran's concerns regarding the JCPOA and urges all sides to implement it fully," the Chinese diplomat said.
He noted that the JCPOA parties can resist US unilateralism, if they all adhere to the deal and cooperate.
Song also held the US responsible for the recent tensions in the Middle East.
The region has been experiencing an escalation over the past few months involving several tanker attacks and seizures, as well as drone incidents.