WASHINGTON — The Biden administration on Sunday told Texas to stop impeding U.S. Border Patrol access to a portion of the U.S.-Mexico border that state National Guard took over last week.

In a letter to Texas Attorney General Ken Paxton, obtained by NBC News, Department of Homeland Security General Counsel Jonathan Meyer said a combination of Texas National Guard soldiers, equipment, and physical barriers are unconstitutionally restricting Border Patrol access to about 2.5 miles of the U.S.-Mexico border.

“The recent actions by the State of Texas have impeded operations of the Border Patrol,” Meyer wrote. “Those actions conflict with the authority and duties of Border Patrol under federal law and are preempted under the Supremacy Clause of the Constitution.”

Meyer added: “Texas’s actions also improperly seek to regulate the federal government. I am writing to demand that Texas immediately cease and desist any actions taken by the State that block Border Patrol’s full access to the U.S.-Mexico border in and around the Shelby Park area.”

Meyer noted an incident on Friday involving the fatal drowning of a woman and two children in the Rio Grande in Eagle Pass, Texas. 

“Texas’s failure to provide access to the border persists even in instances of imminent danger to life and safety,” Meyer wrote. “Texas has demonstrated that even in the most exigent circumstances, it will not allow Border Patrol access to the border to conduct law enforcement and emergency response activities.”

The letter was first reported by CNN.

Federal officials on Saturday confirmed the death of a woman and two children who drowned in the Rio Grande. The DHS said U.S. Border Patrol agents were prevented from entering the area from the U.S. side after Texas National Guard Troops, under the direction of Texas Gov. Greg Abbott, prevented them from responding. The Texas Military Department disputed the DHS statement, saying that its personnel were made aware of a distress report, but could not locate migrants who needed help in the river.

In response to the death of the migrants who drowned near Eagle Pass, a White House spokesperson said in a statement that it is “clear” that Abbott’s “political stunts are cruel, inhumane and dangerous.”

“On Friday night, a woman and two children drowned near Eagle Pass, and Texas officials blocked U.S. Border Patrol from attempting to provide emergency assistance,” the spokesperson said. “While we continue to gather facts about the circumstances of these tragic deaths, one thing is clear: Governor Abbott’s political stunts are cruel, inhumane, and dangerous. U.S. Border Patrol must have access to the border to enforce our laws.”

The letter comes as Abbott and some congressional Republicans have called attention to record numbers of migrants crossing into the U.S. and have blamed the Biden administration for what they described as an open-border policy. 

As part of his immigration enforcement plan, dubbed Operation Lone Star, Abbott’s administration has bused thousands of migrants to Democratic-led cities and has arrested migrants on trespassing charges.

House Speaker Mike Johnson this month led a group of House Republicans to the border in Texas as part of efforts to criticize the Biden administration’s approach to immigration laws amid record migrant crossings.