Three fire trucks responded to a report of a suspicious odor or smoke emanating from a residential townhouse at 2123 F St., this morning.

The event resulted in the closure of F Street between 21st and 22nd streets for more than an hour while D.C. fire officials and engineers investigated the issue.

The origin of the suspicious odor is not yet known, said Sean Greene, the battalion chief who was at the scene.

“There was an odor or smoke in the building and we are unsure where it was at this time, engineers are remaining on the scene.” Greene said. “There was not a fire.”

More than a dozen firefighters and a number of University Police Department officers responded to the scene, lining F Street and the surrounding block with six trucks and a mobile fire investigation unit.

The building had recently been under construction, and it is unclear if it is currently being used as a residence.

As onlookers stopped to watch, fire officials raised the fire ladder to the top of the townhouse then lowered it as firefighters went in through the front of the building to the second floor.

The ladder came back up again about 15 minutes later and two fire fighters climbed the ladder and went onto the roof of the townhouse, but the ladder was lowered shortly after.

Fire officials cleared the scene after about an hour.

The incident disrupted normal D.C. bus circulation for more than an hour, leaving more than two dozen people stranded on at the corner of F and 21st streets in front of the Dakota.

“I don’t like waiting, but things happen,” said Kisia Coke, who was waiting for the bus for almost an hour. “There’s so many of us out here blocking the walkway, it makes us look bad for no apparent reason to wait this long.”