The two National Guard soldiers and a Border Patrol agent who were killed in a helicopter crash Friday in southern Texas were on a flight that was considered a routine mission supporting federal border operations, officials said Saturday.

The crash, which occurred at 2:50 p.m., also seriously injured a third National Guard soldier, according to a statement on X, formerly Twitter, by Gen. Daniel R. Hokanson, chief of the National Guard Bureau. The names of those onboard have not been released.

The helicopter, a UH-72-Lakota, which is a light utility aircraft, was on a mission near Rio Grande City, according to Joint Task Force North, an operation under the U.S. Defense Department that supports Customs and Border Protection with National Guard units.

The crash was unrelated to Operation Lone Star, the border program led by the state of Texas.

The flight was “providing monitoring and detecting capabilities along that sector of the border,” Maj. Ryan Wierzbicki, a spokesperson for Joint Task Force North, said by email. All three people killed had been deployed to the southwest border since October, he said.

The helicopter was patrolling the border and following people who were crossing into the United States illegally when it crashed in an open field, said Judge Eloy Vera, the top local official in Starr County, where the crash occurred.