China is unlikely to put pressure on Tehran to agree to US demands to salvage the Iran nuclear deal despite a recent warning from Washington that time is running out to reach agreement, diplomatic observers believe.
The latest round of talks over the Joint Comprehensive Plan Of Action (JCPOA) began in Vienna in late November and have been continuing over the past week.
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Late last month US National Security adviser Jake Sullivan said there may be only "weeks" left before the talks were no longer "viable".
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But the US can only negotiate through the other signatories - China, Russia, Britain, Germany, France and the European Union- because Iran refuses to talk directly to the Americans.
The 2015 deal imposed curbs on Iran's nuclear programme in return for sanctions relief. But Donald Trump walked out on the deal in 2018 and then imposed further sanctions on Tehran.
Iran said in June that it had enriched uranium to 60 per cent- a significant step towards the nuclear weapons-grade level of 90 per cent.
Tehran has said it will curtail its nuclear programme if Washington lifts the post-2018 sanctions but argues the US has not provided sufficient guarantees it will not walk away from the deal again.
China - which said it had "reached a broad consensus" with Russia and Iran before the latest round of talks - has criticised Washington for walking away from the deal and given Tehran an economic lifeline by buying its oil in defiance of US sanctions.
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Beijing moved closer to Iran last year by signing a Comprehensive Strategic Partnership agreement in March.
Wu Bingbing, a senior research fellow at Peking University's Institute of International and Strategic Studies, said these developments have not changed China's role in the nuclear discussions.
"China's stance on the security of Iran and the region at large has always been coherent, but new elements and proposals have been added [to the relationship]. Questioning what China can do to help forge the deal is not correct. China has an interest in boosting relations with Iran regardless of the deal. " Wu said.
"It is not reasonable to convince any country to sign up for something it does not see as favourable to their national interest. The same people who question whether China is doing enough should also question if the European countries are doing enough to convince the US to amend its demands."