U.S. President Barack Obama has called for a meeting of G7 leaders in The Hague, conspicuously leaving out Russia, which is a member of the G8 group. The United States and the European Union already have imposed some travel and economic sanctions on Russia, but analysts say these are not likely to reverse Moscow's decision on Crimea.
Russian flags are billowing over Crimea's official buildings, local banks are beginning to switch from Ukrainian hryvnia to the Russian ruble, and on March 30, Crimea is slated to adopt Moscow standard time, moving its clocks two hours ahead.
Ilan Berman, vice president of the the American Foreign Policy Council in Washington, said there is no doubt the Russian-speaking majority on the peninsula supports those changes.
"Realistically speaking, the demographics of Crimea and also the politics of how the referendum occurred, I think — there was obviously a very heavy Russian hand — but even absent a certain Russian influence on Crimea, I think you can see that the plurality of the people see themselves as something other than purely Ukrainian," he said.
Berman says Russians in other parts of the region may want to follow Crimea's example.
"I think certainly there is a dangerous possibility that Crimea is not the end of the story, but the beginning of the story," he said. "You are already seeing stirrings in places like Trans-Dniester in Moldova, where there are echoes of what you saw coming out of Crimea ahead of the referendum, essentially expressing sympathy for Russia, expressing desire for Russia to play a more active political role.
"All of this is emboldening, I think, for Moscow, as it looks abroad for possibilities to revise its territorial borders outward, and is hearing these calls for Russian intervention that are likely to embolden it," he added.
Berman notes that Russia already has a military presence in Moldova's Trans-Dniester region, which proclaimed independence in 1990 and fought a separatist war in 1992. Russian troops entered the region as peacekeepers after the war and have never left.
Berman said Moscow is less likely to encroach on NATO or European Union member nations. Clearly aware of that, Moldovan President Nicolae Timofti urged EU leaders this week to speed up Moldova's European integration.
"In the context of this regional difficulty in which the Republic of Moldova is involved, I agreed with the Romanian president [Traian Basescu] of the need to give impetus to the process of integrating Moldova in Europe," said Timofti.
Russia's move in Crimea has sent waves of concern even among some EU and NATO members, where the memory is still fresh of Soviet invasions of Hungary and Czechoslovakia.
Leaders of the United States, Britain, Canada, France, Germany, Italy and Japan meeting in The Hague Monday and Tuesday will discuss moves to contain Moscow's ambitions and reassure allies in the region.
Former U.S. ambassador to Iraq Christopher Hill says the best way to do that is to speed up the Trans-Atlantic integration in eastern Europe and the Balkans. He singled out Macedonia, whose NATO membership has been blocked by Greece over a name dispute.
"I have always believed that Macedonia, which has acted like a NATO country, needs to be accepted as a NATO country," said Hill.
Analyst Ilan Berman agrees that NATO should fortify its members in eastern Europe, cautioning that Russia's future actions, however, will be determined primarily by its economic power.
Europe and especially Germany could have more impact on Russia's economy than the United States, he added.
"If there is a holding back as a result of Germany's decision to maintain economic ties with Russia, then the sanctions that come out of Brussels are going to be diluted,: Berman said. "They are not going to be as effective as they could be, and Russia is not going to be as deterred as it should be."
Russia's takeover of the Crimean peninsula has sparked the biggest dispute between Moscow and the West since the fall of the Iron Curtain, disrupting more than two decades of diplomatic and economic cooperation between the former Cold War adversaries.