The U.S. Navy issued a rare apology Wednesday after Lemoore residents were startled by a loud boom caused by a jet breaking the sound barrier.

About 10:26 a.m., an F/A-18 Super Hornet assigned to Lemoore Naval Air Station was conducting a training mission when it exceeded the speed of sound, the base said in a statement.

Several Lemoore residents called police to report hearing an explosion, prompting officers to patrol the area where the calls originated, Cmdr. Maggie Ochoa said.

“I personally heard it,” she said.

Because it sounded like a sonic boom, Ochoa called the Navy base and received confirmation that a jet fighter had exceeded the speed of sound.

Both Navy and Federal Aviation Administration regulations prohibit breaking the sound barrier over populated areas.

“Although the noise generated is a public concern, at no time was there risk to the community,” the base statement said. “We apologize to those who were impacted by this occurrence.”

An investigation has begun, the Navy said.

This is the second incident this week involving the naval air station. Monday, a Super Hornet jet crashed into a farm field and caught fire. The pilot safely ejected.

The jet fighter was part of the VFA-14 Tophatters squadron, and the wreckage will remain in the field until investigators are done inspecting it, the base said.