The U.S. Justice Department has threatened legal action against Gov. Greg Abbott over the 1,000-foot floating barrier that the state deployed in the Rio Grande near Eagle Pass earlier this month.

“We write to inform you … that the United States intends to file legal action in relation to the State of Texas’s unlawful construction of a floating barrier in the Rio Grande River,” the Justice Department said in a letter sent to Abbott’s office on Thursday. The department gave the state until 1 p.m. Central on Monday to avoid legal action by responding with a commitment to remove the barrier.

“The State of Texas’s actions violate federal law, raise humanitarian concerns, present serious risks to public safety and the environment, and may interfere with the federal government’s ability to carry out its official duties,” said the letter, which was signed by Assistant Attorney General Todd Kim and Jaime Esparza, U.S. attorney for the Western District of Texas.