A Pentagon police officer was killed on Tuesday during an attack at a bus platform outside the military headquarters that prompted gunfire, a lockdown of the sprawling facility in Virginia and massive police and fire response, the Washington Post reports.

On Tuesday evening, the Pentagon’s press office released a statement confirming the death of a police officer during the attack, which occurred on the bus platform at the Pentagon complex in Arlington, across the Potomac River from Washington, D.C.

“Our thoughts and prayers are with the officer’s family,” the statement said. “Additional information on the officer will be forthcoming, following full next of kin notification.”

At an earlier news briefing, Woodrow G. Kusse, the chief of the Pentagon’s police force, confirmed the attack but offered few details. The force provides security at the complex, which was locked down for about 75 minutes after the shooting.

“This morning at about 10:37 a.m., a Pentagon police officer was attacked on the Metro bus platform,” Chief Kusse said. “Gunfire was exchanged, and there were several casualties.”

“The incident is over, the scene is secure, and most importantly there is no continuing threat to our community,” he said.

The chief declined to offer additional details, citing the continuing investigation.

According to Chief Kusse, the F.B.I. is leading the investigation into the attack.

“At this time, it would be premature to speculate on a motive, and in order to protect the integrity of the investigation, we cannot provide additional details at this time,” Samantha Shero, an F.B.I. spokeswoman, said in a statement. “There is no ongoing threat to the public.”

When pressed to say whether the attack may have been carried out by multiple assailants, Chief Kusse said that his office was not looking for any additional suspects.

A Pentagon spokesman, John Kirby, said Lloyd J. Austin III, the secretary of defense, was at a regularly scheduled meeting with President Biden at the White House at the time of the attack, and was immediately notified by his staff that it had taken place.

The secretary later traveled to the Pentagon and visited the building’s operations center upon his arrival, Mr. Kirby said.

Soon after the Pentagon acknowledged the death of the officer, Mr. Austin released a statement that said that flags at the Pentagon would be flown at half-staff.

“This fallen officer died in the line of duty, helping protect the tens of thousands of people who work in — and who visit — the Pentagon on a daily basis,” the statement said. “He and his fellow officers are members of the Pentagon family, and known to us all as professional, skilled and brave.”

“This tragic death today is a stark reminder of the dangers they face and the sacrifices they make,” he added. “We are forever grateful for that service and the courage with which it is rendered.”