NATO Secretary-General Anders Fogh Rasmussen said on Thursday he was concerned about developments in Ukraine's Crimea and urged Russia not to do anything that would "escalate tension or create misunderstanding", Reuters reported.
Armed men earlier seized the regional government headquarters and parliament on Ukraine's Crimea peninsula and raised the Russian flag.
"I'm concerned about developments in Crimea. I urge Russia not to take any action that can escalate tension or create misunderstanding," Rasmussen said on Twitter.
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