Three people were killed and another was injured Friday when a National Guard helicopter crashed in Texas, near the U.S.-Mexico border.

A UH-72 Lakota helicopter carrying three National Guard members and a U.S. Border Patrol agent crashed about 2:50 p.m. local time while conducting operations near Rio Grande City, according to a news release from Joint Task Force North, based in Fort Bliss.

Two of the National Guard members and the Border Patrol agent were killed. The third Guard member was injured.

The cause of the crash is under investigation, according to the release. A spokesman for the task force declined to comment on the condition of the injured Guard member.

In a statement on Saturday, President Biden said he and first lady Jill Biden were praying for the injured service member’s recovery, and he expressed his “profound” gratitude for the work of those killed.

Joint Task Force North, which includes active and reserve military personnel, is tasked with supporting federal law enforcement agencies in stopping suspected criminal activities “within and along the approaches to the continental United States.”

The Starr County Sheriff’s Office earlier said in a short social media statement that it was assisting with a “downed helicopter incident,” possibly involving four occupants.