A Chinese envoy on Wednesday urged all parties concerned to redouble their efforts to advance the process of negotiations on bringing the United States and Iran to resume compliance with the 2015 Iran nuclear deal.

Wang Qun, Chinese envoy to the United Nations in Vienna, made the remarks after attending Wednesday's meeting of the Joint Commission on the Joint Comprehensive Plan of Action (JCPOA), or the Iran nuclear deal.

The meeting was chaired by Enrique Mora, the deputy secretary-general and political director of the European External Action Service and attended by representatives from China, France, Germany, Russia, Britain and Iran.

The current negotiations are generally progressing, but there is still some distance away from the goal of reaching an agreement, Wang said, urging that all parties involved should redouble their efforts to translate the goodwill of reaching an agreement into further concrete actions.

The envoy said all parties concerned should uphold a rational and pragmatic attitude and put forward realistic and feasible proposals regarding the lifting of sanctions, measures in the nuclear field and the sequence in which the United States and Iran return to compliance with the nuclear deal in order to promote the formation of a comprehensive and effective plan.

Wang said China also hopes that Iran and the International Atomic Energy Agency will reach a timely arrangement on the extension of the "temporary bilateral technical understanding," which was agreed between the two sides in February.

The Chinese envoy stressed that China has always held an impartial position on the Iranian nuclear issue and will continue to work with all parties to actively promote the negotiation process. At the same time, China will firmly defend its legitimate rights and interests regarding the lifting of sanctions and other aspects, he said.

Wednesday's meeting marked the end of the fourth round of negotiations of the Joint Commission and the participants agreed to reconvene next week.

Mora told journalists after the meeting that the fourth round of talks over the past ten days has been "the longest" and "the most productive."

"We have made substantial progress. There are still things to be worked out," he said.

The European Union official said the spirit of compromise is high and all delegations are very committed. "I think we are on the right track and we will get an agreement," Mora said.

Mikhail Ulyanov, Russia's permanent representative to international organizations in Vienna, also tweeted that the participants at Wednesday's meeting noted that "good" or "significant" progress was made and that an agreement is "within reach."

The U.S. administration under former President Donald Trump withdrew from the JCPOA in May 2018 and unilaterally reimposed sanctions on Iran. In response to the U.S. moves, Iran gradually stopped implementing parts of its JCPOA commitments from May 2019.

The JCPOA Joint Commission began to meet in person on April 6 in Vienna to continue previous discussions in view of a possible return of the United States to the JCPOA and on how to ensure the full and effective implementation of the JCPOA.