- It may appear like Russia and China are on Iran's side, but things could still change when they meet face to face, said Asif Shuja of the National University of Singapore's Middle East Institute.
- "The positions of all these powers are not rigid, they may change," he told CNBC.
- Analysts are not expecting a major breakthrough from the talks.
China may appear to be representing Iran's demands at the nuclear talks in Vienna, but it's not clear if Beijing will stay on Tehran's side as their political alliance is not "rock solid," said a political expert at the Middle East Institute in Singapore.
Indirect talks between Iran and the U.S. kicked off on Monday, as the two countries look to revive the 2015 nuclear deal. Iran signed the deal — formally known as the Joint Comprehensive Plan of Action — with the U.S., China, France, Germany, Russia and the U.K.
However, under the administration of President Donald Trump, the U.S. unilaterally withdrew from the pact in 2018 and imposed harsh sanctions on Iran. Since then, Iran has also breached the agreement and increased its uranium stockpile and enriched them to levels beyond the parameters of the JCPOA.
"While the battle is happening between the U.S. and Iran, Iran has been trying to win its own teammates out of these P5 powers, and the U.S. is also doing the same," said Asif Shuja of the National University of Singapore's Middle East Institute, referring to the other signatories.
Analysts are not expecting a major breakthrough from the talks, which broke off on Friday and are set to resume in the middle of next week, according to Reuters.
Tehran has said that all sanctions imposed when the U.S. abandoned the pact three years ago must be lifted, but Washington wants Iran to return to compliance before any relief is given.
"The positions of all these powers are not rigid, they may change," said Shuja, adding that it's not clear right now who is on whose team.
China has appeared to be openly supportive of Iran recently.
On Monday, China's permanent mission to the United Nations and other international organizations said on Twitter that the U.S. should lift all sanctions that are inconsistent with the 2015 deal.
Separately, a Chinese foreign ministry spokesperson openly blamed the U.S. as "the culprit" of the crisis.
China has continued to "amplify or function as an extended voice for some of the ultra hardline Iranian demands," said Behnam Ben Taleblu, a senior fellow at the Foundation for Defense of Democracies.
Speaking to CNBC's "Squawk Box Asia" on Tuesday, he said the success or failure of the United States' strategy toward Iran depends in part on Washington and Beijing's relationship.
There have also been reports of China buying Iranian crude despite U.S. sanctions.
That revenue allows Iran to "say no or take a harder stance at the nuclear negotiating table," Ben Taleblu said.
It may appear like Russia and China are on Iran's side, but things could still change when they meet face to face, Shuja said.
"If it had been rock solid … then the parties would not be going there," he said. "There are chances of a change of stand, as far as all these parties are concerned, because when people meet in person, a lot of give and take happens."
"It's about the wider diplomacy, or the wider objectives of these great powers like Russia and China," he said.
"For Iran, Russia and China are most important. But if you look at it from Russia and China's side, Iran is not the most important player," he added.
That said, he acknowledged that China has been "consistently supporting" Iran.
Amir Handjani, a non-resident fellow at the Quincy Institute for Responsible Statecraft, said the United States' relationship with Russia and China has "frayed quite dramatically" since the nuclear agreement was first signed.
"Iran is using Russia and China as a buffer against the EU and the U.S.," he told CNBC's "Capital Connection" on Monday.
— CNBC's Natasha Turak contributed to this report.