Texas officials say a helicopter carrying three National Guard members and a Border Patrol agent crashed along the US-Mexico border, killing three on Friday.

The names of those killed were not immediately released.

According to a statement released by Joint Task Force North, the UH-72 Lakota helicopter was assigned to the federal government’s border security mission when it went down near Rio Grande City.

Starr County judge Eloy Vera said a fourth person was critical in the wake of the crash.

He added that the local sheriff had secured the site, and federal officials were coming to the scene.

The Starr County Sheriff’s Office confirmed on social media that it was assisting with a “downed helicopter incident”.

Texas Department of Public Safety lieutenant Christopher Olivarez said the crash occurred near La Grulla but did not provide further details.

He instead referred questions to the US Customs and Border Protection agency.

The names of those killed were not immediately released.

Head of the National Guard Bureau, Daniel Hokanson, sent his condolences to the families, loved ones, friends and colleagues of the three people killed.

He also issued a prayer for the injured soldier.

“We mourn these heartbreaking deaths,” he said in a post on X, formerly known as Twitter.

“They are a tragic loss beyond words. All of these people represent selfless service and the best of America.”

In January, a Texas Department of Public Safety helicopter patrolling the state’s border with Mexico lost power and crashed.

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 governor Greg Abbott’s nearly 10 billion dollar (£7.7 billion) border mission that has tested the federal government’s authority over immigration.

Border patrol spokespersons did not immediately return messages seeking comment.

The cause of the crash is now under investigation.