A massive debris fire that broke out Wednesday night in Phoenix temporarily forced highway closures as firefighters battled the blaze.

Firefighters responded to the 2-alarm fire near I-10 and 19th Avenue west of downtown Phoenix and found a pile of railroad ties fully engulfed, the Phoenix Fire Department said.

NEW ORLEANS STEAMBOAT THE NATCHEZ ERUPTS IN FLAMES

Phoenix Arizona fire

Multiple agencies responded to the 2-alarm fire. (FOX10 Phoenix)

The blaze forced the closure of both directions of I-10 late Wednesday, the Arizona Department of Transportation said. 

Arizona Phoenix fire

The massive blaze temporarily closed I-10 west of downtown Phoenix. (Arizona Department of Transportation )

The agency announced that both directions were reopened just before 2:30 a.m. Thursday.

Images of firefighters working to extinguish the fiery mound were taken by the fire department and FOX10 Phoenix.

Phoenix Arizona fire

It was unclear what started the blaze. (FOX10 Phoenix)

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Fire officials said the cause of the fire was under investigation.