Ukraine crisis: Protests as tensions escalate
Ukraine is sending security officials to the eastern cities of Donetsk, Luhansk and Kharkiv, after pro-Russian demonstrators stormed government buildings.
On Monday, rebels occupying Donetsk's regional government building declared a "people's republic" and called for a referendum on secession from Ukraine to be held by 11 May.
The country's interim Prime Minister Arseniy Yatsenyuk has blamed Russia for the seizures, accusing it of trying to "destabilise" Ukraine.
Mariko Oi reports.