Firefighters work at the scene of a fire in Alexandria, Virginia, the United States, on Feb. 8, 2020. Several fire units are responding to a "4-alarm townhouse complex fire" in Alexandria, eastern U.S. state of Virginia, on Saturday, according to Arlington County Fire Department. (Xinhua/Liu Jie)

 

Firefighters work at the scene of a fire in Alexandria, Virginia, the United States, on Feb. 8, 2020. Several fire units are responding to a "4-alarm townhouse complex fire" in Alexandria, eastern U.S. state of Virginia, on Saturday, according to Arlington County Fire Department. (Xinhua/Liu Jie)

 
Firefighters have contained a massive building fire in the Alexandria section of Fairfax County, eastern US state of Virginia, fire authorities said Saturday.

Fire crews are hitting hotspots and units are expected to remain on scene for an undetermined length of time, Fairfax County Fire and Rescue Department tweeted Saturday afternoon.

The four-alarm fire broke out in a five-story townhouse complex construction site on Saturday morning, according to authorities.

"Because the unfinished building is lacking usual fire walls and sprinkler systems, fire spread was rapid and intense," Arlington County Fire Department said in a tweet.

Firefighters work at the scene of a fire in Alexandria, Virginia, the United States, on Feb. 8, 2020. Several fire units are responding to a "4-alarm townhouse complex fire" in Alexandria, eastern U.S. state of Virginia, on Saturday, according to Arlington County Fire Department. (Xinhua/Liu Jie)

 

Firefighters work at the scene of a fire in Alexandria, Virginia, the United States, on Feb. 8, 2020. Several fire units are responding to a "4-alarm townhouse complex fire" in Alexandria, eastern U.S. state of Virginia, on Saturday, according to Arlington County Fire Department. (Xinhua/Liu Jie)

 
Thick black smoke was seen kilometers away from the site.

Traffic has been shut down in both directions nearby.

No civilian or firefighter injuries have been reported.

Fairfax County, in Northern Virginia, borders both the City of Alexandria and Arlington County and forms part of the suburban ring of Washington, D.C.