Russian President Vladimir Putin and his Ukrainian counterpart Petro Poroshenko will meet with top EU officials in Belarus next week.
Poroshenko's office said leaders would use the August 26 meeting to discuss ways to stabilise the situation in eastern Ukraine, energy security and Kiev's new trade deal with the European Union, which Russia has opposed.
The news came as Ukraine yesterday said that fighting had erupted in the heart of the major rebel stronghold of Lugansk as government forces pressed on with a punishing offensive to win back the war-torn east.
If confirmed, any advance by Ukraine's army into Lugansk, which has endured brutal shelling and weeks without running water or electricity, would be a major breakthrough for Kiev after four months of fighting that has claimed over 2,100 lives.
A controversial Russian aid convoy was meanwhile still stuck waiting to be checked near Ukraine's restive border as haggling over whether it could cross dragged on.