The FBI is trying to determine why a black SUV carrying three people tried to enter a top-secret intelligence site at Fort Meade, but officials said they don't believe terrorism was the reason.

The unauthorized vehicle at the National Security Agency's campus prompted shots to be fired at the vehicle Wednesday morning. The driver was hospitalized, though NSA and FBI officials say they don't believe any injuries were caused by bullets. Two other occupants were taken into custody.

"We are making a determination as part of the ongoing investigation as to what happened leading them on to the NSA compound and then what happened once they got on the compound," said Gordon Johnson, special agent in charge of the FBI's Baltimore field office. "I cannot emphasize enough that we believe there is no indication that this has a nexus to terrorism."

Authorities have not released the names of any of the individuals involved. Johnson said they were male, but didn't release ages.

Dave Fitz, an FBI spokesman, said the vehicle could have made a wrong turn and ended up at the NSA gate.

"That is certainly one of the theories we are looking at," he said in a text message response to a question about the possibility of a wrong turn leading to the confrontation.

The NSA campus — in suburbs edged by woods outside the nation's capital — sits by a highway with an exit specifically designated for NSA employees. But drivers have taken the wrong exit before and ended up at the tightly secured gates. Most motorists then carefully follow the orders of heavily armed federal officers and turn around without getting into further trouble.

But in early 2015, two people were shot by NSA police when they disobeyed orders outside the heavily secured campus. One driver died at the scene after NSA police opened fire on a stolen sports utility vehicle. Authorities later said they had stolen a car from a man who picked them up for a party at a motel.

An NSA police officer and a civilian onlooker also were injured in the incident Wednesday. Both required hospital treatment, but their injuries were not life-threatening, Johnson said. He added that he didn't know the medical condition of the driver.

The incident began about 6:55 a.m. when the vehicle tried to enter the spy agency's campus.

While Johnson declined to give details about who opened fire, he said preliminarily indications are that all gunfire was directed toward the vehicle.

Images from local news outlets showed authorities surrounding two handcuffed people after a black SUV ran into a barrier outside the campus. After the shooting, authorities closed a major highway in both directions, causing major backups locally during rush hour.

The vehicle had a New York license plate, and Johnson said it was believed to be a rental car, but he said it was unknown exactly where the vehicle came from.

"We are working through that," Johnson said. "We believe that it was a rental car, but we're still working that as part of the ongoing investigation."