Crimea, Ukraine (BBN)-Pro-Russian activists in eastern Ukraine have seized state security buildings in the cities of Donetsk and Luhansk, Ukrainian officials say.
Reports say that in Luhansk the protesters have raided the arsenal in the security building. Police have reacted by blocking roads into Luhansk.
On Sunday protesters broke into the regional government buildings in the two cities and also Kharkiv.
Ukraine's acting president has called an emergency security meeting.
Tensions have escalated in eastern Ukraine in recent weeks. Russia is consolidating its grip on Crimea, annexed by Moscow last month, and thousands of Russian troops remain massed near the Ukrainian border.
Ukrainian authorities say protesters have now left the government building in Kharkiv.
But in Luhansk on Monday police said "unknown people who are in the building have broken into the building's arsenal and have seized weapons".
Ukraine's interim President Olexander Turchynov cancelled a visit to Lithuania to deal personally with the unfolding events.
BBN/ANS/AD/07Apr14-3:30 pm (BST)