President Obama spoke about the Ukraine crisis Friday afternoon, saying, "The United States will stand with the international community in affirming that there will be costs for any military intervention in Ukraine." Mark Wilson/Getty Images hide caption

itoggle caption Mark Wilson/Getty Images

Viktor Yanukovych, who says he's still the president of Ukraine, at his news conference Friday in the southern Russian city of Rostov-on-Don. Yuri Kochetkov /EPA /LANDOV hide caption

itoggle caption Yuri Kochetkov /EPA /LANDOV

On Friday, armed men took control of the international airport in the city of Simferopol, on the Crimean peninsula. Gunmen took control of another airport in Crimea, as well. David Mdzinarishvili/Reuters/Landov hide caption

itoggle caption David Mdzinarishvili/Reuters/Landov

Flags fly outside the Crimean parliament building in Simferopol on Thursday during a rally by pro-Russian protesters. Gunmen seized government buildings in the city. David Mdzinarishvili /Reuters/Landov hide caption

itoggle caption David Mdzinarishvili /Reuters/Landov

People pass by a portrait of prominent opposition leader Yulia Tymoshenko at Independence Square in Kiev, Ukraine, on Monday. Tymoshenko, a former prime minister, is one of the leaders who have emerged after the ouster of President Viktor Yanukovych, but she is also a controversial figure. Marko Drobnjakovic/AP hide caption

itoggle caption Marko Drobnjakovic/AP

Russia RUS-1 bobsled team, with Alexander Zubkov, Alexey Negodaylo, Dmitry Trunenkov, and Alexey Voevoda, jump onto the medal stand after winning gold on Sunday. On the last day of the Sochi Games, Russia had already secured the top spot in the overall medal count. Dita Alangkara/AP hide caption

itoggle caption Dita Alangkara/AP

Putin greets his Syrian counterpart, Bashar Assad, in Moscow on Dec. 19, 2006. Russia has remained a steadfast ally of Assad despite three years of civil war and Western calls for Assad's ouster. Mikhail Klimentyev/AP hide caption

itoggle caption Mikhail Klimentyev/AP

Anti-government protesters clash with police on Independence Square in Ukraine's capital Kiev early Wednesday. The protests have been going on for three months, and Tuesday was the deadliest day yet, with at least 25 reported killed. Sergei Supinsky/AFP/Getty Images hide caption

itoggle caption Sergei Supinsky/AFP/Getty Images

Maria Alyokhina (left) and Nadezhda Tolokonnikova of Pussy Riot on stage at Amnesty International's "Bringing Human Rights Home" concert earlier this month in Brooklyn, N.Y. Jason Szenes /EPA/Landov hide caption

itoggle caption Jason Szenes /EPA/Landov