Ukrainian troops and police officers are on high alert, after armed men seized government buildings in the Crimea region of the country and raised a Russian flag over a barricade.
Acting president Oleksander Turchinov told parliament on Thursday he had given an order for security structures to take "all measures" needed to protect citizens.
Al Jazeera's Robin Forestier-Walker reports from Simferepol in the Crimea region.
