China has played a uniquely constructive role in the historic nuclear deal concluded on Tuesday in Vienna, Austria, between Iran and six world powers, according to Chinese Foreign Minister Wang Yi.

The long-awaited agreement with China, Britain, France, Germany, Russia and the United States, known as the P5+1, aims to limit Iran's nuclear program in exchange for the gradual suspension of sanctions.

"Today is a historic day," Wang told reporters after the agreement, as posted on the Foreign Ministry's website.

Wang believes the most important achievement of the agreement is that it protects the global non-proliferation system. While Iran made a political commitment not to develop nuclear weapons, it has been given the right to peaceful use of nuclear energy.

"It is also turning a new page of Iran's relationship with the other parties," Wang said.

Wang, who has been shuttling between the nuclear talks in Vienna and the BRICS summit and Shanghai Cooperation Organization meeting in Ufa, Russia, last week, said the agreement succeeded because it adhered to the principle of a political solution despite difficulties and complexities.

He said the agreement has been a useful practice for the international community to solve major disputes through dialogue, and it also set a good example for solving other global and regional hot spot issues, including the denuclearization of the Korean Peninsula.

"This comprehensive accord carries significance far beyond the Iranian nuclear issue itself," Wang said.

Wang expressed that China has participated in the whole process of the negotiation in a constructive manner. And China's uniquely constructive role has won praise from all the parties. But he also said that there is still much to do in implementing the deal, and he hopes that all the parties will earnestly implement their commitments.

In Washington, there was a backlash on Tuesday in the Republican-controlled Congress to the 100-page accord. Congress has a 60-day review period and could hold a vote of disapproval and take further action. But President Barack Obama said on Tuesday he will veto moves by Congress to block the Iran deal.

Obama said the US and its international partners achieved something that decades of animosity have not - a comprehensive, long-term deal with Iran that will prevent it from obtaining a nuclear weapon.

"I want to thank our negotiating partners - the United Kingdom, France, Germany, Russia, China, as well as the European Union - for our unity in this effort, which showed that the world can do remarkable things when we share a vision of peacefully addressing conflicts. We showed what we can do when we do not split apart," Obama said.

Brian Katulis, a senior fellow at the Center for American Progress, believes a successful deal on the Iran nuclear issue could serve as a test case for more cooperation between China and the US in the Middle East.

The Center for American Progress, China US Exchange Foundation and the Shanghai Institutes for International Studies released a report on Monday exploring ways that China and the US could cooperate in the Middle East.

Some experts also believe the agreement will enable a revitalized, sanction-free Iran to boost trade and cooperation with China. The sanctions have slashed the Middle East country's oil exports and crippled its economy.

Shada Islam, policy director of the Brussels-based think tank Friends of Europe, said China could help Iran mitigate the impact of the sanctions by providing short-term "emergency aid".

This would help to meet shortfalls in the health sector and supply urgently needed essential items.

"In the long run, the focus will of course be on the development of Iran's infrastructure and oil and gas sector," Islam said. "Given its location and diverse regional interests, Iran will also inevitably play a crucial role in China's (new) Silk Road proposal."

An Huihou, a former Chinese ambassador to Egypt, said Iran has a strong desire to participate in China's Silk Road initiatives amid Tehran's ambitious plans to revive its economy.

Closer economic links would also boost the "going global" strategy of Chinese enterprises and further elevate China's ties with other Middle East countries, An added.

Iran, a key stop on the ancient Silk Road, has joined the China-led Asian Infrastructure Investment Bank as a founding member.

Two-way trade reached a record $51.8 billion last year, up 31.5 percent from 2013. The major products that China, the world's largest energy consumer, imports from Iran include crude oil and iron ore. Iran has the world's fourth-largest oil reserves and the second-largest reserves of natural gas.

Fraser Cameron, director of the Brussels-based EU-Asia Center, said the Iranian economy has outstanding prospects because of its abundant oil and a young, dynamic population. The gradual lifting of sanctions will help it to realize that potential.

"It could quickly become a major economic power in the Middle East," Cameron said. "It occupies a key geostrategic situation and could be an important hub for the new Silk Road initiatives. China-Iran relations could also develop quickly since they have complementary economies."

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