"On Wednesday, June 18 at approximately 11 p.m. CT, the Starship preparing for the tenth flight test experienced a major anomaly while on a test stand at Starbase. A safety clear area around the site was maintained throughout the operation and all personnel are safe and accounted for," SpaceX wrote on X early Thursday morning. 

The reason for a static fire test comes ahead of an upcoming launch in which the rocket's engines are fired while the rocket remains securely held down on the launch pad — essentially a rehearsal for the real launch.