THE HAGUE, Netherlands (AP) -- Seeking to isolate Russia, President Barack Obama and Western and Asian allies moved to indefinitely cut Moscow out of a major international coalition on Monday, including canceling an economic summit President Vladimir Putin planned to host this summer.
The moves came amid a flurry of diplomatic jockeying as the U.S. and Europe grappled for ways to punish Russia for its annexation of the Crimean Peninsula and to prevent Moscow from pressing further into Ukraine. The world powers warned that they were prepared to "intensify actions" against Russia, including ordering more severe economic sanctions, if the Kremlin escalates its incursion into Ukraine.
Separately in the Hague, in an unexpected development, Russia's foreign minister met with his Ukrainian counterpart, the highest level of contact between the two nations since Russia moved forces into Crimea nearly a month ago.
Obama huddled with the leaders of Britain, France, Germany, Italy, Canada and Japan for an emergency meeting of the Group of Seven. In a joint statement after the evening meeting, the leaders said they were suspending their participation with Russia in the Group of Eight major industrial nations until Moscow "changes course."
The G-7 leaders instead plan to meet this summer in Brussels, symbolically putting the meeting in the headquarters city of the European Union and NATO, two organizations seeking to bolster ties with Ukraine.
"Today, we reaffirm that Russia's actions will have significant consequences," the leaders' statement said. "This clear violation of international law is a serious challenge to the rule of law around the world and should be a concern for all nations."
Russia's actions have sparked one of Europe's deepest political crises in decades and drawn comparisons to the Cold War era's tensions between East and West. Obama and other Western leaders have condemned Russia's movements as a violation of international law and have ordered economic sanctions on Putin's close associates, though those punishments appear to have done little to change the Russian leaders' calculus.
Hours before world leaders began meeting in The Hague, Russian forces stormed a Ukrainian military base in Crimea, the third such action in as many days. Ukraine's fledgling government responded by ordering its troops to pull back from the strategically important peninsula.
In the U.S., meanwhile, the Senate moved toward a vote on Russia sanctions and Ukraine aid while Ukraine pushed for the United Nations General Assembly to adopt a resolution, possibly on Thursday, reaffirming the country's territorial integrity and declaring that the referendum in Crimea that led to its annexation by Russia "has no validity."
In the Hague, the G-7 leaders also discussed plans for increasing financial assistance to Ukraine's central government.
Obama was expected to be seeking support from European leaders for deeper sanctions on key sectors of the Russian economy, including its energy industry.
But the U.S. leader was expected to face resistance from some European officials. Russia is one of the European Union's largest trading partners and officials fear that the still economically shaky continent could suffer if Moscow retaliates, particularly by curbing oil and gas supplies.
In another attempt to isolate Russia, Obama held a separate meeting Monday with Chinese President Xi Jinping, whose country frequently sides with Moscow in disputes with the West.
The U.S. has been appealing to China's vehement opposition to outside intervention in other nations' domestic affairs and scored a symbolic diplomatic gain when Beijing abstained a week ago from voting on a United Nations Security Council resolution declaring Crimea's secession referendum illegal. With Russia vetoing the measure and the 13 other council members voting in favor, China's abstention served to isolate Moscow internationally.
"I believe ultimately that by working together, China and the United States can help strengthen international law and respect for the sovereignty of nations and establish the kind of rules internationally that allow all peoples to thrive," Obama said while standing alongside Xi ahead of their hour-long meeting.
In a counterpoint to Obama and his G-7 partners, a group of five major emerging economies - Brazil, Russia, India, China and South Africa - issued a statement Monday opposing sanctions and urging nations to work through the U.N. instead. The so-called BRICS nations said hostile language, sanctions and force do not "contribute to a sustainable and peaceful solution."
The scheduled purpose for Obama's long-planned trip to the Netherlands was the two-day Nuclear Security Summit, an international forum the president created during his first term that focuses on eliminating or securing the world's nuclear materials. While the nuclear talks were overshadowed by the dispute with Russia, Obama did score a key victory on that front Monday when Japan announced that it was turning over to the U.S. a portion of its weapons-grade plutonium and highly-enriched uranium stockpiles.
Obama arrived in the Netherlands Monday morning after an overnight flight from Washington. He opened his visit with a stop at Amsterdam's Rijksmuseum, where he admired Rembrandt's massive 17th-century painting "Night Watch."
The president's weeklong trip also includes stops in Brussels, where he'll meet with European Union leaders, and Rome, where he'll have an audience with Pope Francis. He'll close his trip in Saudi Arabia, a visit aimed at soothing tensions with a key Gulf ally.