The Interstate 40 bridge linking Arkansas and Tennessee was shut down Tuesday afternoon after authorities said they found a crack in the span.

The Arkansas Department of Transportation tweeted that it found the crack during a routine inspection of the bridge over the Mississippi River. The department said it was working with the Tennessee Department of Transportation to ensure the bridge is safe before it reopens.

Arkansas Department of Transportation spokesman Dave Parker said the bridge would be closed at least through Tuesday night. The Tennessee Department of Transportation said the crack was found in the bottom side of the bridge truss.

Transportation officers and police block an Interstate 40 onramp to the bridge over the Mississippi River near downtown Memphis, Tenn., on Tuesday, May 11, 2021. The Arkansas Department of Transportation tweeted on Tuesday that it found a crack during a routine inspection of the bridge. (AP PhotoAdrian Sainz)

Transportation officers and police block an Interstate 40 onramp to the bridge over the Mississippi River near downtown Memphis, Tenn., on Tuesday, May 11, 2021. The Arkansas Department of Transportation tweeted on Tuesday that it found a crack during a routine inspection of the bridge. (AP PhotoAdrian Sainz)

Traffic was backed up for miles in both directions because of the closure. River traffic was also shut down until further notice, the Tennessee Department of Transportation said.

Parker said the bridge had passed its last inspection in September. Drones were being used to take a closer look at the crack, Parker said.

Traffic was being rerouted to the Interstate 55 bridge over the river, about three miles south of the I-40 span.