A colossal fire engulfed downtown Los Angeles, Calif. early on Monday, burning down an apartment tower that was still under construction, damaging two other buildings on a neighboring street and closing freeways, according to LA Times.

The California Highway Patrol warned motorists that the 101 southbound is closed at Alvarado Street and the 110 Freeway is closed between the 10 and 101. Officials are concerned that pieces of the buildings may collapse onto the freeways.

Over 250 firefighters are battling the blaze that started at around 1:20 a.m. PST (4:20 a.m. EST) on the 900 block of Fremont Avenue, Los Angeles Fire Department spokesman David Ortiz told LA Times.

"It's huge," he said.

As of the time of publication, the fire is still smoldering and officials cannot predict when it will be fully extinguished.

The cause of the fire is unknown and there have been no reports of injury thus far. Arson investigators are on scene, as is protocol for massive fires.