Russia today said Washington would be making a grave mistake by pulling out of the Iran nuclear deal, adding that it would work hard to keep the landmark agreement alive. Deputy Foreign Minister Sergei Ryabkov said Russia will do everything in its power to save the agreement.<br/><br/>Under the hard-won 2015 deal with Russia, the US, China, France, Britain, Germany and the EU, Iran agreed to curb its nuclear programme in exchange for the lifting of a raft of international sanctions. America's allies see the accord as the best way to thwart Iran's nuclear ambitions and a victory for multilateral diplomacy. Tehran categorically denies it is seeking to develop atomic weapons.<br/><br/>Ryabkov said Moscow must unite with Europe and China and undertake "intense work" to keep the existing plan intact and decried what he said was a US attempt to strongarm the situation.