"In the current situation, we believe that all parties should maintain calm and restraint to avoid escalating the Iran nuclear situation, or even walking towards confrontation and conflict," foreign ministry spokeswoman Mao Ning told a regular briefing.

Beijing will host Russia and Iran for trilateral talks on Tehran's nuclear programme on Friday.

The meeting will be attended by China's Vice Foreign Minister Ma Zhaoxu, Russian Deputy Foreign Minister Sergey Ryabkov and Iranian Deputy Foreign Minister Kazem Gharibabadi.

The United States withdrew from a landmark deal that had imposed curbs on Iran's nuclear programme in return for sanctions relief during President Donald Trump's first term, which ended in 2021.

Tehran adhered to the 2015 deal for a year after Washington's withdrawal but then began rolling back its commitments.

Efforts to revive the pact have since faltered.

However, Beijing said the talks would aim to "strengthen communication and coordination, to resume dialogue and negotiation at an early time".

"China sincerely hopes that all parties can work together, continuously increase mutual trust and dispel misgivings, and turn the momentum of restarting dialogue and negotiation into reality at an early date," Mao said.