CORONADO, Calif. — A driver was taken into custody at the main entrance to Naval Air Station North Island Tuesday amid an investigation into materials found inside a vehicle, a U.S. Navy official said.

Around 9 a.m., security guards stopped a car at the gate on Third Street and inside, discovered materials that appeared to be for making explosives, Naval Base Coronado spokesman Kevin Dixon told FOX 5. No bombs were found.

Naval Criminal Investigative Services took the driver into custody and were investigating the materials.

The main gate on Third Street and the outbound gate on McCain Boulevard to 4th Street were closed for the investigation, but since have reopened, the base said in a Facebook post. The gates on First Street and Ocean Boulevard remained open for the duration.

“I would like to thank all the interagency partners for helping,” said Capt. Dwight “Woody” Clemons, a commanding officer for Naval Base Coronado. “We train to these types of scenarios on a regular basis.  A recent example of that is the annual Solid Curtain-Citadel Shield- force protection exercise we’ve just conducted over the last two weeks.”

Closures remain at the commercial vehicle inspection lanes at the main gate. The visitor control center also is expected to remain closed until Wednesday, officials said.