Accession of Russia's neighbours Ukraine and Georgia to Nato could lead to deployment of tactical nuclear weapons on their territory and trigger a new arms race, the Kremlin's security chief said in an interview.
Security Council chief Nikolai Patrushev said in an interview with Izvestia daily, to be published on Thursday, that Washington and Nato sought to achieve military and strategic supremacy over Russia by extending the alliance's borders.
"Georgia and especially Ukraine in case of their accession to the alliance can become a convenient springboard for deployment of large ground, air and naval strike forces armed with high-precision and tactical nuclear weapons," he said.
"Potential deployment of such weapons in Ukraine will make them strategic, because their destruction zone will cover critically important military and economic objects in European Russia, with elements of state governance and military command," Patrushev said.
"Such actions by the Americans can aggravate mutual mistrust and spiral (into) an arms race to which we do not aspire, I want to stress."
At a summit in Bucharest in April, Nato members turned down requests from former Soviet republics Georgia and Ukraine to be granted a Membership Action Plan, which would have set them on the road to membership. But they held open the possibility of future entry.
Patrushev, a long-term ally of powerful Prime Minister Vladimir Putin and former FSB secret service chief, also warned that a possible US strike on Iran from Georgian land would lead to "additional threats to Russia's national security".
Russia's relations with the West, already strained by Nato's eastward expansion and a planned US missile shield in eastern Europe, soured further in August after Moscow's brief war against Georgia.
Moscow further irked the West by recognising Georgia's two breakaway regions – Abkhazia and South Ossetia – as independent states.