Kremlin spokesman Dmitry Peskov said President Vladimir Putin remained committed to the agreement and that there were no alternatives "at the moment" to the deal.

"Putin has repeatedly spoken about the consequences of ill-considered steps towards Iran, meaning the decision taken by Washington" to reimpose sanctions, Peskov said.

He said Russia would work with European countries to maintain the "continued viability" of the nuclear deal and that it was too early to discuss the possibility of Russia joining sanctions against Tehran.

"Putin has said that it is ill-conceived and arbitrary decisions that put unreasonable pressure on Iran and cause the adverse steps that we are facing."