MOSCOW: Russian Deputy Foreign Minister Sergei Ryabkov said on Tuesday that Moscow would respond harshly to a US decision to expel 60 Russian diplomats, but was still open to strategic stability talks with Washington, the RIA news agency reported. The United States said on Monday it would expel 60 Russian diplomats, joining governments across Europe in punishing the Kremlin for a nerve agent attack on a former Russian spy in Britain that they have blamed on Moscow.