A tornado killed a two-year-old boy and injured his mother on Wednesday when a tree fell on their house in suburban Detroit.

It comes as emergency workers in Maryland were responding to reports of collapsed structures with people trapped inside after a tornado there.

Officials in Livonia, Michigan, said in a post on the city’s website that the quick-developing tornado struck several neighbourhoods in the city on Wednesday afternoon.

A massive tree was uprooted and fell onto the family’s house and through the roof, landing on a bed where the woman and her two-year-old were sleeping, officials said.

Crews worked for nearly an hour to remove the roof and parts of the tree and then lift the tree to get the victims out.

The toddler was pronounced dead at the scene, officials said. The mother was transported to a local hospital in critical condition.

A two-week-old sibling who was in a crib in a separate room was not injured but taken to a hospital for an evaluation, Livonia Fire Department chief Robert Johnson told WDIV-TV.

“This is a terrible tragedy for our community,” mayor Maureen Miller Brosnan said in the statement.

“Our hearts are broken, too, and we send our deepest sympathies.”

The city of Livonia activates warning sirens based on notifications from the National Weather Service or tornado reports, officials said.

However, Livonia Emergency Preparedness director Brian Kahn said in a statement that the city did not receive any advance warning from the agency or others.

A representative from the weather service called it a spin-up storm that did not show up on their radars in enough time to issue a warning, according to city officials.

In the state of Maryland, emergency workers were responding to reports that people were trapped inside structures that collapsed after a tornado was spotted in the area during rounds of strong storms on Wednesday night.

A tornado was spotted in a suburban area of Montgomery County northwest of Washington, the National Weather Service said in a social media post warning people in the area to take cover.

There were reports of three collapsed structures in Gaithersburg with people trapped inside, Montgomery County Fire and Rescue Service spokesperson Pete Piringer said.

Mr Piringer said the most significant damage occurred when a large tree fell on a single-family house in Gaithersburg, leaving five people injured, including one with traumatic injuries. He said they were all taken to hospital.

Local television footage showed large downed trees that damaged houses when they fell.

Tornado warnings were still being issued throughout the state and in Delaware on Wednesday night.