Migrants who crossed the Rio Grande from Mexico walk past large buoys deployed as a border barrier on the river in Eagle Pass, Texas, on July 12.  Eric Gay/Associated Press

AUSTIN, Texas (AP) — The Justice Department on Monday sued Texas Gov. Greg Abbott over a newly installed floating barrier on the Rio Grande that is the Republican’s latest aggressive tactic to try to stop migrants from crossing into the U.S. from Mexico.

The lawsuit asks a federal judge in Austin to force Texas to remove a roughly 1,000-foot line of bright orange, wrecking ball-sized buoys that the Biden administration says raises humanitarian and environmental concerns. The suit claims that Texas unlawfully installed the barrier without permission between the border cities of Eagle Pass and Piedras Negras, Mexico.

The buoys are the latest escalation of Texas’ border security operation that also includes razor-wire fencing, arresting migrants on trespassing charges and sending busloads of asylum-seekers to Democratic-led cities in other states. Critics have long questioned the effectiveness of the two-year operation, known as Operation Lone Star. A state trooper’s account this month that some of the measures injured migrants has put the mission under intensifying new scrutiny.

In anticipation of the lawsuit, Abbott sent President Biden a letter earlier Monday that defended Texas’ right to install the barrier. He accused Biden of putting migrants at risk by not doing more to deter them from making the journey to the U.S.

“Texas will see you in court, Mr. President,” Abbott wrote.

The Biden administration has said illegal border crossings have declined significantly since new immigration restrictions took effect in May. In June, the first full month since the new polices took effect, U.S. Customs and Border Protection said migrant encounters were down 30% from the month prior and were at the lowest levels since Biden’s first full month in office.

White House press secretary Karine Jean-Pierre told reporters that Abbott’s policies as a whole have made it difficult for U.S. Border Patrol agents to access Rio Grande.

“Those are unlawful actions that are not helpful and is undermining what the president has put forward and is trying to do,” she said.

In a letter last week, the Justice Department gave Texas until Monday to commit to removing the barrier or face a lawsuit. The letter said the buoy wall “poses a risk to navigation, as well as public safety, in the Rio Grande River, and it presents humanitarian concerns.”

The state deployed the buoys without notifying the International Boundary and Water Commission or the U.S. Army Corps of Engineers. Mexico’s secretary of state asked the federal government to intervene, saying the barrier violates international treaties.

The lawsuit is not the first time the Biden administration has sued Texas over its actions on the border.

U.S. Attorney General Merrick Garland in 2021 accused the state of usurping and even interfering with the federal government’s responsibility to enforce immigration laws after Abbott empowered state troopers orders to stop vehicles carrying migrants on the basis that they could increase the spread of COVID-19.