What's the latest on the Metrobus fire near the National Mall in DC?

Friday morning commuters are still dealing with the effects from a Metrobus fire Thursday that sent smoke over downtown Washington DC.

Here's what to know about the fire and its impact on Friday's commute.

What caused the fire Thursday in Washington DC?

A Metrobus caught fire around 6:30 p.m. Thursday in the 9th Street tunnel under the National Mall, officials said in a press conference.

The cause of the fire is unknown, but it's believed to be from a mechanical issue. Officials said the bus was fully engulfed in flames.

WMATA said no customers were aboard the bus, and the operator escaped without injury.

Although no passengers were in the bus, FOX 5 DC reported drivers in the tunnel were forced to abandon their vehicles and flee as smoke filled the area.

"The flash happened, then the fire started. (In that moment) the tunnel started filling with smoke," Ashley Jamieson told WUSA. "I was like, we really need to all move, so like everyone move out of the way, drive ahead." 

Video shared by the DC Fire and EMS Department showed heavy black smoke emerge from the tunnel.

The fire was extinguished by around 8 p.m.

Are roads still closed because of the fire in Washington DC?

The 9th Street tunnel remained closed Friday morning, with the Metropolitan Area Transportation Operations Coordination Program saying drivers should "expect an extended closure."

Alternate routes include 12th Street to access Maine Avenue SW and 7th Street SE to get on the eastbound freeway, according to WJLA.

All 32 hybrid diesel buses in the WMATA fleet were removed out of an abundance of caution and will be inspected.

WMATA said late Thursday it was working with its manufacturer and bus team on plans "to mitigate any impacts to bus service."

“We are a very safe system; we know that we are. With that said, it’s happened. We want to work with our partners," WMATA General Manager and CEO Randy Clarke said. "We’ll do forensic investigations. We will learn from investigations. And we get better.”