A separatist-run news agency cited emergency services official Sergei Ivanushkin as saying today that the separatist-held parts of Luhansk region have seen a spate of accidents recently because of careless use of explosives.
Ivanushkin said a man and woman were hospitalised after yesterday's incident.
The blast occurred at a "cheburechnaya", a restaurant serving fried pastries, that also offered duckpin bowling, which uses a ball without holes on a relatively short lane.
East Ukraine has been wracked by war for almost a year, during which the region has become flooded with small arms and grenades.