Russia has threatened NATO with military strikes in Poland and Romania if a missile defence radar and interceptors are deployed in Eastern Europe.
General Nikolai Makarov, Russia's most senior military commander, warned NATO that if it proceeded with an American missile defence system, force would be used against it.
"A decision to use destructive force pre-emptively will be taken if the situation worsens," he said.
General Makarov has threatened to target NATO bases hosting an anti-missile system designed by the US to protect European allies against attack from states such as Iran.
He said that Russia would counter NATO deployment by stationing short-range Iskander missiles in the Russian Kaliningrad enclave near Poland, creating the worst tensions since the Cold War.
"The deployment of new strike weapons in Russia's south and northwest -- including Iskander systems in Kaliningrad -- is one of our possible options for destroying the system's European infrastructure," he said.
John McCain, the US senator and chairman of the senate foreign relations committee, said Russia's threats were an "excuse to have a military build-up in this part of the world".
"It is really an egregious example of what might be even viewed as paranoia on the part of Vladimir Putin," he said on a visit to Lithuania.
The chief of the Russian general staff drew up a detailed analysis, presented to the Alliance, that claims to show the NATO system could eliminate Russian missiles by the end of the decade.
"A thorough analysis showed that once the third and fourth stages are deployed, the capability to intercept Russian intercontinental ballistic missiles will be real," he said.
The missile defence row has dogged relations between Moscow and Washington for a decade and has threatened to derail Barack Obama's overture to "reset" diplomatic ties.
Anatoly Serdyukov, the Russian defence minister, warned yesterday that Russia-NATO negotiations on the anti-missile system had reached an impasse. "We have not been able to find mutually-acceptable solutions at this point and the situation is practically at a dead end," he said.
Russia's threat to militarise the dispute came as a special American and NATO team began Moscow talks before next month's official deployment of the first elements of the new missile shield.
Alexander Vershbow, NATO's deputy secretary general, tried to reassure Russia that the new system was not even able to target Russian intercontinental ballistic missiles.
"Our NATO system is neither designed against, nor directed at Russia," he said. "[General Makarov's] briefings are based on the false assumption that the NATO system can launch before the burnout of an attacking ballistic missile, which is simply not the case."
Russia is vehemently opposed to the NATO and American system billed as defending European Alliance members from nuclear threats from Iran or North Korea.
Makarov's hard line has raised concerns it could herald a hardening of attitudes, or even a new Cold War, in the transition from Dmitry Medvedev back to Vladimir Putin. (© Daily Telegraph, London)