Five people were in the residential building were when the rocket struck, Interfax Ukraine news agency quoted a security official in the port as saying. A second child was taken to hospital.
The official said the blast damaged windows, walls and the roof of the adjacent Orthodox church.
The Secretary of Ukraine’s Security Council, Oleksiy Danylov, quoted by media, confirmed there had been dead and injured in the attack. The strike, he said, had blown the roof off the church.
(Reporting by Kyiv bureauEditing by Ron Popeski and John Stonestreet)