Sergey Ryabkov said that Washington’s statements about a potential resumption of full-scale nuclear testing could trigger a self-sustaining chain reaction in this field MOSCOW, April 20. /TASS/. Moscow maintains a strict commitment to the moratorium on nuclear testing but will respond in kind should the US or other countries violate said moratorium, Russian Deputy Foreign Minister Sergey Ryabkov said. "Russia, for its part, maintains a strict commitment to the national moratorium on nuclear