Moscow: Russia's top diplomat, Sergey Lavrov, announced on Tuesday that Russia will respond to Ukraine's alleged use of US-supplied long-range ATACMS ballistic missiles against Russian territory. This follows claims by Moscow that it downed six of these missiles above the Bryansk region, which, if confirmed, would be the first such attack by Kyiv since the Russia-Ukraine conflict began 1,000 days ago. According to Anadolu Agency, Lavrov expressed at a news conference following a G20 summit in Rio that Russia believes these missiles cannot be launched without US military involvement. He stated that such actions would mark a 'qualitatively new stage' in what he termed the West's war against Russia. Lavrov emphasized that Russia views nuclear weapons as a deterrent to nuclear war, hinting that the West should familiarize itself with Moscow's revised nuclear doctrine, which was publicly announced by President Vladimir Putin over a month ago. Lavrov also noted that the updated nuclear doctrine has been legally f ormalized and urged Western nations to read it in its entirety. He stressed that the doctrine does not introduce new concepts unknown to the West and aligns with American nuclear policy documents. Earlier on Tuesday, Putin signed a decree approving Moscow's updated nuclear doctrine, following his announcement of changes during a conference on nuclear deterrence on September 25.