Ukrainian forces have launched an "all-out attack" on pro-Russian rebels near the city of Donetsk, Ukraine's interior minister has announced.
According to AFP, the interior ministry said the military push was launched "across several parts of the front" near Donetsk and the neighbouring city of Lugansk.
The attack follows a warning to the Pro-Russian separatists by the Ukrainian government that it planned to regain control of the areas.
The Ukrainian Donetsk and Luhansk regions, on the border with Russia, held disputed referendums on 11 May in which most voters supported independence from Ukraine.
Violence escalated in the region following the outbreak of unrest between pro-government forces and rebels in April.
Both sides have been accused of violating a 10-day ceasefire offered by newly-elected Ukrainian president Petro Poroshenko on 20 June.
Donetsk's pro-Russia separatists have vowed to keep fighting Ukrainian government forces.