And Moscow added to its sudden military bravado when Defense Ministry Sergei Ivanov told the country's top brass that Russia retained the right to stage pre-emptive strikes against other countries under certain circumstances.
Ivanov's comments only confirmed Russia's existing military doctrine.
But the tough talk was jarring because it came only days after Russian President Vladimir Putin and his US counterpart George W. Bush held a Camp David summit in which the two men reaffirmed their personal friendship and let their old dispute over Iraq drop.
Russia's military command appeared far more hawkish.
"Should NATO remain a military alliance with its current offensive military strategy, this will prompt a fundamental reassessment of Russia's military planning and arms procurement," said an internal document released by Russia's defense ministry.
This re-evaluation will include "changes to Russia's nuclear strategy," the document said, without spelling out how Russia's approach to nuclear weapons could change.
Russia and the United States agreed in May 2002 to slash their nuclear arsenals by two-thirds to between 1,700 and 2,200 warheads over the next decade.
Moscow has established warmer relations with NATO over the past two years and has joined a special Russia-NATO Council where it enjoys a broad advisory role, but no veto power.
But the Russian defense ministry -- which often expresses more hardline views than President Vladimir Putin's administration -- said it still regarded NATO as a threat as the alliance eyes expansion into former Soviet republics in the Baltic region -- Estonia, Latvia and Lithuania.
"Russia is carefully following NATO's transformation, and expects it to put a complete end to direct and indirect elements of its anti-Russian policy, which includes its military planning," the document said.
The ministry demanded that anti-Russian sentiments were also removed from the "political declarations" of NATO member state.
Meanwhile, Putin issued an unusual warning while attending a meeting of the defense ministry's top brass in Moscow.
"I would like to inform you about what the defense minister, chief of general staff and the head of the Russian strategic rocket division already know," Putin told his military audience.
"Russia has a significant supply of heavy strategic rockets," Putin said in reference to the UR-100 N (NATO classification SS-19) that can carry up to six nuclear warheads.
"We are talking about the most threatening rockets, and we have tens of them, with hundreds of warheads," news agencies quoted the president as saying.
Putin said those rockets had never been put on military alert.
But another senior military official said they could become the backbone of Russia's nuclear deterrence system for the next three decades.
It was not immediately clear why Putin decided to say publicly for the first time that Russia had these rockets in reserve.
The Russian defense minister for his part told the same meeting that Russia must be prepared to fight simultaneous wars on two fronts and resort to pre-emptive strikes should events warrant, just like the United States.
"We cannot absolutely rule out the pre-emptive use of force if this is dictated by Russia's interests or its commitments to allies," Ivanov said.