A tanker truck fire shut down I-95 in both directions after an elevated portion of the heavily traveled interstate collapsed in Philadelphia on Sunday morning, state officials said, raising concerns about possible travel headaches throughout the Northeast.

The Pennsylvania Department of Transportation said the fire closed all lanes between Exit 25 and Exit 32, which includes Allegheny Avenue, Castor Avenue, Academy Road, and Linden Avenue.

Philadelphia Fire Department Captain Derek Bowmer said emergency crews responded shortly before 6:30 a.m. local time after receiving a report of a vehicle being on fire on the interstate. Authorities later identified the vehicle as a gasoline tanker truck that may have been carrying hundreds of gallons of gasoline.

The fire took about an hour to get under control. City and state officials are “responding to address impacts to residents in the area and travelers affected by the road closure,” the state fire department said in a statement to USA TODAY.

In a Sunday night update, Pennsylvania Gov. Josh Shapiro said at least one vehicle was still trapped under the collapsed roadway but there were no immediate reports of injuries. “We’re still working to identify any individual or individuals who may have been caught in the fire and the collapse,” he said.

Interstate 95 is the main north-south highway on the East Coast and stretches from Florida through Maine to Canada.

“Travelers should expect delays and plan alternative travel routes, especially while planning for their weekday commute,” the City of Philadelphia Office of Emergency Management said.

Transportation Sec. Pete Buttigieg said he was monitoring the fire and collapse and was in touch with the governor and Federal Highway Administration to offer “help with recovery and reconstruction.” And the National Transportation Safety Board said it was working with the Pennsylvania State Police to conduct a safety investigation.

President Joe Biden was also briefed on the collapse and officials offered assistance to local and state authorities, according to White House press secretary Karine Jean-Pierre.

How did the section of I-95 in Philadelphia collapse?

Transportation Department spokesperson Brad Rudolph said some kind of crash occurred on a ramp under northbound I-95 causing the northbound section above the fire to quickly collapse.

Bowmer said runoff from the fire or compromised gas lines caused explosions underground. Because of heat from the fire, Bowmer said the northbound lanes were gone and the southbound lanes were “compromised.”