Russia has said it is concerned over the US statement on reviewing the Iran nuclear deal with its European allies. Deputy Foreign Minister Sergei Ryabkov told reporters that Moscow will continue to back the deal, and oppose any attempt to hamper it. The EU has said the nuclear deal is working. Meanwhile, the Chairman of the Russian Federation Council's Foreign Affairs Committee, Konstantin Kosachyov, also slammed the U.S. attempt to review the deal as a dangerous violation of international law. Both the US and Russia are among the six powers that signed the deal in 2015 after years of negotiations.