More than twenty people were killed in eastern Ukraine on the eve of the peace talks that are scheduled to take place in Minsk on Wednesday.

The Ukrainian army lost nineteen soldiers, the majority of them killed near the key transport hub of Debaltseve, which has been surrounded by the separatists, the BBC reports.

The shelling of a bus station in Donetsk on Wednesday morning left six people dead and eight others injured, TASS news agency reports.

Casualties were also suffered in the city of Kramatorsk, where a rocket attack killed both soldiers and civilians.

The meeting of the so-called Normandy format will bring together Ukrainian President Petro Poroshenko with his Russian counterpart Vladimir Putin, German Chancellor Angela Merkel and French President Francois Hollande.

The talks have been identified as one of the last chances for ending the conflict peacefully.

The summit is expected to negotiate a ceasefire and withdrawal of heavy weapons as well as the establishment of a demilitarised zone.