A small aircraft belonging to the Mexican Navy crashed on Monday near Galveston, Texas, resulting in the deaths of at least five individuals. The plane was transporting a young medical patient and seven others when it went down, prompting a search and rescue effort off the Texas coast, according to authorities.

Among the eight people onboard, four were Navy personnel and the remaining four were civilians, including a child. The Mexican Navy provided these details in a statement to The Associated Press. However, U.S. Coast Guard Petty Officer Luke Baker has not confirmed which individuals have been identified among the deceased.

Two passengers were affiliated with the Michou and Mau Foundation, an organization dedicated to assisting Mexican children suffering from severe burns.

The accident occurred on Monday afternoon close to the start of a causeway near Galveston, situated roughly 50 miles southeast of Houston along the Texas coastline. The cause of the crash remains under investigation.

The Mexican Navy revealed that the plane was engaged in a medical mission when the “accident” happened. They have vowed to look into the circumstances surrounding the incident and are collaborating with local authorities in the ongoing search and rescue operations.

Officials from the Federal Aviation Administration and the National Transportation Safety Board have arrived at the crash site, as reported by the Texas Department of Public Safety on the social media platform X.

A spokesperson from NTSB said they are “aware of this accident and are gathering information about it.”

The Galveston County Sheriff’s Office said officials from its dive team, crime scene unit, drone unit and patrol were responding to the crash. It said in a post on Facebook that the public should avoid the area so emergency responders can work safely.

Galveston is an island that is a popular beach destination.

It’s not immediately clear if weather was a factor. The area has been experiencing foggy conditions over the past few days, according to Cameron Batiste, a National Weather Service meteorologist. He said that at about 2:30 p.m. Monday, a fog came in that had about a half-mile visibility.