Ukraine in crisis | U.S. to Russia: 'It is an act of aggression; it must stop'

A day after Ukraine's interim prime minister called Russia's military intervention "a declaration of war," a Russian fleet has reportedly issued an ultimatum to Ukrainian forces in Crimea: Surrender or "face storm."

U.S. and Russian ambassadors exchanged sharp words at the United Nations in New York on Monday. Vitaly Churkin, Russia's ambassador to the U.N., said ethnic Russians are under attack in the Ukraine from "anti-national radicals" and defended the possible use of force in Crimea.

"We're talking about defending our citizens and our compatriots, on defending the most important human right, the right to life," Churkin said.

"There is no evidence that ethnic Russians are in danger," U.S. ambassador Samantha Power responded. "Russia is trying to convince the world community that up is down, and black is white.

"What is happening today is a dangerous military intervention in Ukraine," Power continued. "It is an act of aggression. It must stop."

Both pro-and anti-Russian demonstrators gathered in the Ukrainian city of Odessa on Monday. The pro-Russian group, carrying Russian flags and chanting "referendum," were refused entry to a government building. Supporters of the new government in Kiev gathered behind them, as police kept the two protests apart.
Under article 4 of the Treaty, any Ally can request consultations whenever, in the opinion of any of them, their territorial integrity, political independence or security is threatened. The developments in and around Ukraine are seen to constitute a threat to neighboring Allied countries and having direct and serious implications for the security and stability of the Euro-Atlantic area.

For some cable news viewers, it isn't an international crisis until Anderson Cooper gets there. Cooper arrived in Kiev Monday to anchor CNN's coverage, reporting that Ukrainians in the capital city are "giving their names to authorities saying they are willing to fight" the Russians.
“It’s the most important, most difficult foreign-policy test of his presidency,” R. Nicholas Burns, former under secretary of state in the George W. Bush administration, told the New York Times. “The stakes are very high for the president because he is the NATO leader. There’s no one in Europe who can approach him in power. He’s going to have to lead.”
At a meeting at the Oval Office with Israeli Prime Minister Benjamin Netanyahu, President Barack Obama says Russia is "on the wrong side of history," and that its actions in the Ukraine violate international law.

"If they continue on the trajectory" they are on, Obama said, the United States is examining a range of options to "isolate" Russia.

Obama said the U.S. and Secretary of State John Kerry, who is traveling to Kiev, have made it clear to Russia that Putin's aggression has consequences.
Pro-Russian protesters demanding a split from Kiev stormed a government building in the east Ukraine's city of Donetsk on Monday, Reuters reports:

The chaotic scene in the heart of Ukraine's Russian-speaking east was one of the boldest actions yet by pro-Russian youths after several days of rallies in eastern and southern cities that Kiev says are organized by Moscow as a pretext to invade. The protesters stormed the building and reached the second floor where the regional council sits, despite efforts to keep them out by switching off lifts and sealing stairwell doors.
Protesters waved Russian flags and chanted "Putin come."
"In addition to other measures we are taking in response to the situation in Ukraine, the United States will no longer send a Presidential Delegation to the upcoming Winter Paralympic Games in Sochi. President Obama continues to strongly support all of the U.S. athletes who will participate in the Paralympics and wishes them great success in the Olympic competition."
The United States says Russia's reported threat to the Ukrainian navy would be "dangerous escalation," the Associated Press reports. "Moscow would be responsible."
The European Union has posted conclusions from its emergency meeting of foreign ministers in Brussels. Among them:

1. The European Union strongly condemns the clear violation of Ukrainian sovereignty and territorial integrity by acts of aggression by the Russian armed forces as well as the authorisation given by the Federation Council of Russia on 1 March for the use of the armed forces on the territory of Ukraine. These actions are in clear breach of the UN Charter and the OSCE Helsinki Final Act, as well as of Russia's specific commitments to respect Ukraine's sovereignty and territorial integrity under the Budapest Memorandum of 1994 and the bilateral Treaty on Friendship, Cooperation and Partnership of 1997. These actions are also a clear breach of the Ukrainian constitution which specifically recognises the territorial integrity of the country and states that the Autonomous Republic of Crimea can only organise referenda on local matters but not on the modification of the territorial configuration of Ukraine.

2. The EU calls on Russia to immediately withdraw its armed forces to the are as of their permanent stationing, in accordance with the Agreement on the Status and Conditions of the Black Sea Fleet stationing on the territory of Ukraine of 1997. Russia should also without delay agree to the request by Ukraine to hold consultations, as foreseen in the bilateral Treaty on Friendship, Cooperation and Partnership of 1997, and to take part in urgent consultations among all signatories and adherents of the Budapest Memorandum of 1994.

3. The EU calls for a peaceful solution to the current crisis and full respect of the principles of and obligations under international law.