WASHINGTON (AFP) - A tornado has left several people critically injured and serious damage in Alabama, United States media said on Tuesday (Jan 26).

The storm, which hit the town of Fultondale late on Monday night, caused "significant damage", the National Weather Service (NWS) tweeted.

At least five people have been hospitalised with critical injuries, Fultondale Police Chief D.P. Smith told local news media AL.com.

"It looks like a bomb went off," local pastor's son Sam Moerbe, 18, told the outlet.

Pictures on social media showed homes and buildings reduced to splinters, wrecked cars and blocked roads.

Fultondale's Fire Chief Justin McKenzie told ABC 33/40 the town had been "hit bad, multiple injuries, multiple houses, trees, people trapped".

Rescuers were still working into Tuesday morning - with the authorities urging people to stay away from the area to allow emergency services to get to work.

"We do still have people trapped in houses," the city's mayor Larry Holcomb told the New York Times.

Neighbouring fire service Homewood tweeted it was sending "units to assist with search and rescue operations after the storms",

An NWS tornado watch remains in place for many of Alabama's counties into Tuesday.