"We need to determine … parameters of the work within the JCPOA without the United States. We believe that this is possible not only theoretically, but practically," Ryabkov told the Valdai discussion club.
The official noted that Moscow firmly believed that any separate agreements to revise the JCPOA were impossible.
"Russia does not consider itself bound by possible, hypothetical separate agreements concluded by any party within the JCPOA. I mean the failed attempt of the E3 states to reach an agreement with the United States on improving the deal," Ryabkov said.
The diplomat also stressed that Moscow feared that the US withdrawal from the deal with Iran might “become a prelude to the further escalation of military tensions in the Middle East.”
READ MORE: Lavrov: US Decision to Withdraw From Iran Nuclear Deal Violates UNSC Resolutions
The leaders of France, Germany and the United Kingdom expressed their regret over Trump's decision in a joint statement, stressing their countries' commitment to the JCPOA.
On July 14, 2015, the European Union and the P5+1 group of countries — China, Germany, France, Russia, the United Kingdom and the US — signed the JCPOA with Iran. The agreement stipulated a gradual lifting of anti-Iranian economic sanctions in exchange for Tehran curbing its nuclear program and allowing inspections to ensure that the nature of the program is peaceful.