Police believe an attempted arson attack on a block of flats may have been racially motivated and three people have been arrested.
Block of flats at Watton where Portuguese families live
A primitive incendiary device containing fireworks was left on a landing at the block of flats where the majority of residents are Portuguese.
The block of flats called the Old Brewery is in the middle of the High Street at Watton, Norfolk.
Police said if the fire had spread it could have caused a serious incident.
A forensic investigation is under way and a number of possibilities are being looked into, police have said.
Supt Nick Dean said: "With a large number of Portuguese people living in the building we have to investigate the possibility it may have been a racially motivated attack."
No-one was reported as injured after the fire was put out quickly by the fire service.
The plastic container on a communal landing was packed with fireworks, nails, screws and bolts.
A police spokesman said the residents were being cared for at a centre in nearby Thetford.
Three men have been arrested and will be questioned by detectives on Friday, the spokesman said.