A National Guard soldier from New York who was seriously injured in the crash of a helicopter flying over the U.S.-Mexico border remained hospitalized Sunday while authorities released the names of the two National Guard soldiers and a Border Patrol agent who were killed.

The three killed Friday in the crash near Rio Grande City were: Chief Warrant Officer 2 Casey Frankoski, 28, and Chief Warrant Officer 2 John Grassia, 30, both with the New York National Guard; and Border Patrol Agent Chris Luna, 49. The cause of the crash remains under investigation.

The UH-72 Lakota helicopter was assigned to the federal government’s border security mission when it went down, according to a statement released by Joint Task Force North, a military unit that supports Customs and Border Protection.

The injured soldier was from the New York National Guard, according to the National Guard Bureau. The soldier, whose name isn’t being released, was the aircraft crew chief. The soldier remained hospitalized, according to a release posted by the New York State Division of Military & Naval Affairs.

Major General Ray Shields, the adjutant general of New York, said in the release that they are “shocked and devastated” by the deaths of Frankoski and Grassia, and are “praying for the quick recovery” of the injured crew chief.

U.S. Customs and Border Patrol Commissioner Troy Miller said in a statement that they were “heartbroken” by the death of Luna, who is survived by his wife and two children, parents and brother.

Secretary of Homeland Security Alejandro Mayorkas said in a statement that they are hoping for the injured national guardsman’s “swift recovery,” and said his thoughts and the “deepest condolences” of the department were with the families of those killed.

Grassia, who was a New York state trooper, was from Schenectady, New York, and he enlisted in the New York Army National Guard in 2013 as a UH-60 Black Hawk helicopter maintenance specialist, according to the New York State Division of Military & Naval Affairs. The release said that Frankoski, of Rensselaer, New York, enlisted in the New York Army National Guard in 2016 and she trained to become a UH-60 Black Hawk and UH-72 Lakota helicopter pilot.

New York Gov. Kathy Hochul said in a statement that she was “deeply saddened” by the deaths of Grassia and Frankoski.

“There is no greater calling than service to and defense of your country,” she said.

Frankoski and Grassia were assigned to Detachment 2, Company A, 1st Battalion, 244th Aviation Regiment. Luna was assigned to the Border Patrol’s Rio Grande City Station.

The helicopter that crashed was assigned to the District of Columbia Army National Guard, according to the New York State Division of Military & Naval Affairs release.

The border region is heavily patrolled by both state and federal authorities, including routine aerial surveillance.

In January, a Texas Department of Public Safety helicopter patrolling the state’s border with Mexico lost power and crashed, officials said at the time. The co-pilot suffered a minor hand injury and the helicopter was significantly damaged. That helicopter was flying as part of Operation Lone Star, Texas Gov. Greg Abbott’s nearly $10 billion border mission that has tested the federal government’s authority over immigration.