Russian President Vladimir Putin will discuss Tehran's nuclear program with his Iranian counterpart Masoud Pezeshkian in China on Monday, a meeting that comes as Iran faces fresh Western pressure.

Britain, France and Germany have moved to reimpose sanctions on Iran, saying the country is failing to comply with a 2015 nuclear deal.

Moscow on Friday backed its key ally, warning that the reimposition of sanctions risked "irreparable consequences".

"We strongly urge them to reconsider and review their erroneous decisions before they lead to irreparable consequences and further tragedy," Russia's foreign ministry said in a statement.  

It accused the European trio of undermining diplomatic efforts to find a peaceful solution to the stand-off over Iran's nuclear program.

The Kremlin later said that Putin would meet Pezeshkian on the sidelines of a Shanghai Cooperation Organisation (SCO) summit in the Chinese city of Tianjin on Monday.

Russia, a permanent member of the UN Security Council, is a party to the 2015 Joint Comprehensive Plan of Action or JCPOA, which provided Iran with sanctions relief in exchange for curbs on its nuclear program.

The three countries, also dubbed the E3, notified the UN Security Council on Thursday that they "believe Iran to be in significant non-performance of its commitments" under the agreement, according to a letter seen by AFP.

The foreign ministers invoked the process known as "the 'snapback' mechanism," which initiates a 30-day deadline for reimposing sanctions that had been suspended under the 2015 deal.

Iran warned that it would "respond appropriately" to the move, which risks drawing a curtain on the most sustained diplomatic push for a peaceful solution to the Iranian nuclear crisis.

Tehran and Moscow have been bolstering political, military and economic ties over the past decade as Russia drifted away from the West. Relations between the two countries grew even closer after Russia launched its offensive in Ukraine.