It was later spread to the gas station and other buildings in Accra, said the media report. According to initial reports the fire erupted accidentally.
Firefighters battled the blaze into the early hours while police and soldiers joined emergency crews helping rescue people trapped in the wreckage, said city Mayor Oko Vanderpuije.
Floods from several hours of heavy rains submerged buildings and vehicles across the city on Wednesday.
Death toll from fire likely to rise as the search for bodies continues.