A U.S. Navy medic shot and critically injured two people at an industrial park in Frederick, in the U.S. state of Maryland, on Tuesday before heading to a nearby military base, where he was killed by personnel there, authorities said.

Frederick Police Chief Jason Lando told a news briefing that police responded to a shooting incident around 8:20 a.m. ET at Riverside Tech Park, where a 38-year-old male suspect opened fire, striking two men and causing others to flee. It was not yet clear whether the shooting happened inside or outside the business.

The suspect then drove about 10 minutes to Fort Detrick, a military installation that houses most elements of the U.S. Army's biological defense program, where he was fatally shot by "personnel on the base," Lando said.

"We have two different scenes. All I can tell you is that we have confirmed there is only one shooter. The public is no longer at risk. Everyone is safe," Lando said.

The U.S. Navy confirmed on Twitter that the shooter was a Navy Hospital Corpsman, and that sailors were involved during the encounter with the shooter.

The two victims in the shooting suffered life-threatening injuries and were flown to the University of Maryland Shock Trauma Center in Baltimore, police said.

Pentagon spokesman John Kirby said it was still too early to give further details. "We still don't have all the facts right now. Information is still coming in," he said.

Special agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) are responding to assist, the ATF's office in Baltimore said on Twitter.

Several schools in the Frederick County Public Schools (FCPS) system were "briefly placed on lockout status," the FCPS said in a tweet.

"All students and staff are safe. The lockout has been lifted."

Frederick Community College (FCC) told students to follow a "lockdown alert" in the immediate aftermath of the shooting, saying later in an updated tweet that students can "return to normal operations. The incident has been contained. There is no threat on FCC campus."

The Frederick Police Department will hold another press briefing in the afternoon to give an update about the incident.