President Donald Trump’s intensifying economic campaign against Iran is testing the limits of the security grouping Xi Jinping and Vladimir Putin have spent years expanding as a counterweight to US power. The Chinese and Russian presidents will gather with their Iranian counterpart Masoud Pezeshkian for the first time since the start of the US and Israeli war against the Islamic Republic at the Shanghai Cooperation Organization summit that starts Monday in Kyrgyzstan. Indian Prime Minister Narendra Modi will also attend along with leaders from Central Asian states, Pakistan and Belarus.

“The message is getting clearer and louder each year that there’s emerging a new security bloc,” said Henry Wang Huiyao, founder of the Center for China and Globalization research group in Beijing. The unipolar world dominated by the US “is gone,” he said. Yet with US Treasury Secretary Scott Bessent threatening an “economic D-Day” of measures to punish Iran and its backers, Tehran’s showdown with Trump risks exposing the SCO’s inability to act coherently as it marks 25 years since its formation.

While the bloc has grown substantially in recent years, rivalry among member states means it’s largely failed to translate that geopolitical ambition into concrete mechanisms for action on the global stage. That’s likely to leave its leaders offering only symbolic solidarity with Tehran at the summit in Bishkek. Neither Xi nor Putin has shown any readiness to back Iran militarily and economic support has been limited. The prospect of further US sanctions is raising the stakes for a group that has sought to challenge the Western-dominated world order.

“We can expect rhetorical condemnation of the US in line with normal Chinese propaganda,” said Jeremy Chan, a senior analyst for China and Northeast Asia at the Eurasia Group. “But Beijing might also be hesitant to shine a spotlight on how ineffective the SCO has been in protecting the security of one of its member countries.”