On his personal twitter account, Bildt called the situation "alarming" and added that "Russia must immediately withdraw forces it controls" to agreed upon area. He wrote that the Crimean capital of Simferopol is "clearly outside this area."
Ukraine's interior minister accused Russia on Friday of staging an "armed invasion" of Crimea, the Associated Press reports, saying Russian troops have taken up positions around a coast guard base and two airports on the Black Sea peninsula.
Armed men took control of two airports in Ukraine's autonomous Crimea on Friday though Russia denied involvement in the seizures. Ukrainian authorities later said they regained control of the airports.