A Ukrainian soldier and a woman died when a grenade exploded in a Kyiv apartment, police in the Ukrainian capital said, but the cause of the blast, which injured a second man, was not immediately clear.

Explosives technicians and investigators were working at the scene of Sunday's explosion in the Dniprovskiy district, Kyiv police said in a statement.

"A citizen contacted the police with a report that an explosion rang out in a neighbouring apartment," they added.

Early this month, an aide to Ukraine's commander-in-chief, General Valery Zaluzhnyi, died when a grenade given to him as a birthday gift blew up. (Reporting by Lidia Kelly in Melbourne; Editing by Clarence Fernandez)