The head of NATO said Wednesday the alliance was worried Russia could extend its intervention beyond Crimea into eastern Ukraine and that the crisis reflected a wider "strategy" by Moscow to exert control in the region.
"Our major concern right now is whether he (President Vladimir Putin) will go beyond Crimea, whether Russia will intervene in the eastern parts. . ." of Ukraine, Secretary General Anders Fogh Rasmussen said during an event in Washington.
Denouncing the moves in the Crimean peninsula as "military aggression," Rasmussen said Russia's actions were part of a long-running campaign across the region to block nations from forging ties with the West.
"If you look at all of this, you will see an overall Russian strategy," he told an audience at the Brookings Institution think tank.
"It serves their long term strategic interests to keep instability in that region that can be used, among other things, to prevent countries in that region to seek Euro-Atlantic integration.
"That's my main concern."
Rasmussen cited a pattern of "frozen, protracted conflicts" in breakaway regions in Georgia, Moldova, Azerbaijan and now Ukraine's Crimean peninsula.
Sending troops into Crimea was part of "a more long-term, Russian or at least Putin strategy," he added.
NATO had suspended staff-level military and civilian meetings with Russia and was reviewing all cooperation with Moscow in light of the crisis, he said.
It was no longer clear if Russia was a partner or an "adversary," Rasmussen said, adding that future NATO deliberations needed "to focus on the long-term strategic impact of Russia's aggression on our own security."
Calling the crisis a "wake-up call" for NATO, he said Russia's intervention marked "the gravest threat to European security and stability since the end of the Cold War."
He also said he was "confident" alliance ministers would agree to bolster assistance to Ukraine at an upcoming meeting but he did not specify what kind of aid might be approved.
US officials have said they are reviewing a request from Kiev for military support, including arms, ammunition and non-lethal equipment.
So far Washington, worried about triggering an all-out war, has only agreed to provide military rations to Ukraine.
To reassure anxious allies, the United States and NATO have announced increased military cooperation with partners in Eastern Europe, including more fighter jets for air patrols over Baltic states.
Rasmussen said he expected "further steps" by NATO to improve the militaries of allies in Central and Eastern Europe.
