RALEIGH, N.C. (WNCN) — Fire crews responded to a fire early Sunday morning in North Raleigh.

At about 6:15 a.m., Raleigh police said they were called to an apartment building on the 9400 block of Prince George Lane near Old Lead Mine Road and Mere Oak Drive across from the Six Forks Station Shopping Center.

When crews arrived at the scene, fire officials said people were stuck on the second floor of the building and at least one person was hanging out the window.

Multiple fire trucks and about at least four EMS vehicles were seen responding.

CBS 17 crews at the scene said there was heavy smoke and the building appeared to be damaged.

Police said four people were taken to the hospital for smoke inhalation. Fire officials said firefighters rescued them from the building and that their injuries were non-life-threatening.

A firefighter was also taken to the hospital as a precautionary measure after sheetrock fell on him, according to the fire department.

He has since been released from the hospital after multiple tests for a probable concussion, they said.

Fire officials said about 21 people were displaced in the fire and the Red Cross responded to the scene.

They said the apartment complex also opened up its community center to help those who live in the building.

The cause of the fire remains under investigation.

As of 7:40 a.m., crews remained at the scene.

By 8:30 a.m., crews started to clear the scene.

CBS 17 has reached out for more information.

This is a developing story. Check back for details.