Beijing, Jun 7 (AFP) Iran, China and Russia may seek ways to salvage the nuclear deal ditched by Donald Trump when their leaders meet this weekend at a summit on the Chinese coast.

The Shanghai Cooperation Organisation (SCO), a regional security bloc led by China and Russia, is set to hold its 18th annual gathering in the city of Qingdao on Saturday and Sunday.

Iran's President Hassan Rouhani is attending this year -- just the second time an Iranian leader has participated.

It comes after US President Trump controversially pulled Washington out of a 2015 international pact with Iran that placed limits on its nuclear programme in return for easing economic sanctions.

China is Iran's top trade partner and one of the biggest buyers of its oil, but those who oppose the US abandonment of the deal risk huge fines for busting the tough American measures.

Rouhani is taking part because "Iran is currently evaluating the signatories of the nuclear deal to see to what extent they'll be able to effectively maintain it even after the US's withdrawal", said Gao Shangtao, an expert on Middle East relations at Beijing Foreign Affairs College.

"To put it bluntly, if Tehran feels assured that China and Russia can withstand the pressure of US sanctions and continue to do business with Iran, then Tehran will seek to retain the deal -- otherwise, it's meaningless," he said.

Chinese businesses are expected to step up activities in Iran to fill the void left by the exit of US companies and the possible withdrawal of European rivals who fear punitive US measures.

Hua Liming, a former Chinese ambassador to Iran, told the Global Times newspaper on Tuesday: "Unlike the US, China will not break its promise and will ensure that China-Iran relations won't be affected."

Iran announced on Tuesday that it plans to boost uranium enrichment capacity with new centrifuges within the 2015 deal's limits, prompting Beijing to urge all parties to "continue to sustain and implement" the agreement.

The SCO bloc includes four ex-Soviet Central Asian republics and two new members, Pakistan and India -- whose President Mamnoon Hussain and Prime Minister Narendra Modi, respectively, will be present this weekend.

Iran is currently an observer member of the SCO, though it has long sought full membership.

"Iran needs more diplomatic support from the East -- not only China, but also Central Asia -- in order to strengthen its position and better contend with the US," said Xu Tiebing, international relations professor at the Communication University of China.

But most Chinese analysts "are not too eager to see Iran accepted as a formal member state" due to its perceived political instability, he added.

Chinese President Xi Jinping will meet Rouhani on the sidelines of the summit, but the nuclear deal is not on the formal SCO agenda.

Major SCO topics will include improving trade ties -- in part by pushing forward China's Belt and Road global infrastructure project -- and strengthening cooperation on drug trafficking, cybersecurity and counter-terrorism.

Despite mistrust between China and Russia, "outside circumstances -- specifically US foreign policy -- have pushed them closer to each other", said Tugrul Keskin, director of the Center for Global Governance at Shanghai University.

Xu agreed, noting US policy under Trump has been the driver of the SCO's growing profile, becoming "a kind of glue" keeping together SCO member countries who have disparate and often conflicting agendas.

Russian President Vladimir Putin told Chinese state broadcaster CGTN that though the SCO began as a "low-profile organisation" that sought merely to "solve border issues" between China, Russia and former Soviet countries, it is now evolving into a larger global force.

"Our objective was quite small, but as we worked together on these small issues, we found similarities between us," he said.

"We realised that together we could achieve something bigger, grander." (AFP)

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