Sloviansk, Ukraine (BBN)-Ukrainian forces have launched an operation against pro-Russian activists who seized a police station on Saturday, the interior minister says.
Arsen Avakov announced on his Facebook page that "all security units" were involved in an "anti-terror operation" in the eastern city of Sloviansk, reports BBC.
Russia warned earlier that any use of force in eastern Ukraine could scupper crisis talks due later this week.
The US accuses Moscow of inciting the trouble. The Kremlin denies the charge.
BBN/ANS/AD/12:45 pm (BST)