Progress made in the negotiations of Iran nuclear talks this week should not be underestimated although "a breakthrough is far from being achieved," a senior Chinese envoy said on Friday.

From Monday to Friday in the Austrian capital Vienna, the P4+1 group (China, Britain, France and Russia plus Germany), the European Union and Iran held in-depth discussions aimed at reviving the 2015 Iran nuclear agreement.

China hopes that each party's consultations with their own governments during the adjournment of the talks until next week will inject new political impetus into the negotiations, said Wang Qun, Chinese envoy to the United Nations and other international organizations in Vienna.

The talks helped other parties to increase their understanding of the position of the negotiation team of Iran's new government, Wang explained.

China hopes all concerned parties will continue to work towards creating a good atmosphere for negotiations, he said.

China will continue to firmly support the resumption of the negotiation process between the United States and Iran, Wang said, and to play a unique and constructive role working with all parties for achieving results at an early date.

During the five-day talks, Iran submitted draft proposals for the 2015 nuclear agreement, from which the United States withdrew in 2018.

However, senior diplomats from Britain, France and Germany on Friday voiced "disappointment and concern after thoroughly and carefully analyzing Iranian proposed changes to the text negotiated during the previous six rounds."

Wang said after the meeting that dialogue on exploring and expanding consensus should be continued by focusing on the text and proposals, even though differences remain.

The previous round of talks over the restoration of the 2015 deal took place in June.

The U.S. government under Donald Trump withdrew from the deal in May 2018 and unilaterally re-imposed sanctions on Iran, which retaliated by gradually stopping implementing elements of the accord since May 2019.