About 30 firefighters are battling to control a blaze at a set of terraced homes in Portsmouth.
Crews from Southsea, Havant and Cosham fire stations were called to Corby Crescent in Anchorage Park shortly before 12.45pm.
A fire service spokesman said a fire had started in a terraced house and had spread to the roofs of two others.
Firefighters had searched the homes but did not find anyone inside.
The crews are still on scene using hose reels and an aerial ladder to try to put out the fire.