The state of Mississippi’s bridges are in such bad shape that the governor has ordered at least 102 closed this week.

Mississippi Gov. Phil Bryant, a Republican, issued an emergency declaration, authorizing the Mississippi Department of Transportation workers to shut down the bridges, with the help of state troopers, if necessary. The department began notifying counties Thursday to shut down the bridges within 24 hours or the state would step in, according to officials.

The dilapidated bridges “create extreme peril to the safety of persons and property,” the governor said in the order. If the bridges aren’t closed, the Federal Transportation Administration has threatened to withhold funding to the state, according to Melinda McGrath, MDOT’s executive director.

The move follows an April 5 letter to Mr. Bryant from Brandye Hendrickson, acting administrator of the Federal Highway Administration, which listed bridges that inspectors determined to be unsafe. The state must close unsafe bridges immediately or the administration “will be compelled to follow-up with consequential actions,” she wrote. Mississippi was the only state to receive such a letter recently, according to a spokesman for the U.S. Department of Transportation, which oversees the highway administration.

Mississippi’s bridge problems mirror the nation’s. As of the end of 2017, 54,560 out of 615,002 bridges nationwide were determined to be “structurally deficient” by the Federal Highway Administration, meaning the bridge needed significant repair. The American Society of Civil Engineers has estimated it would cost $123 billion to repair all the nation’s bridges. In March 2017, the society issued its “Infrastructure Report Card”—released every four years—and gave U.S. infrastructure an overall grade of “D+”—below standard.