(WASHINGTON) -- A Pentagon police officer was stabbed in an attack at the Pentagon Transit Center Tuesday morning and later died, two law enforcement sources told ABC News.
The suspect also died as a result of the incident, law enforcement sources said.
Chief Woodrow Kusse, who leads the Pentagon Force Protection Agency, joined Pentagon spokesman John Kirby at an afternoon press briefing to address the incident, but he would not provide details about casualties, including whether an officer was wounded.
"This morning at about 10:37 a.m., a Pentagon police officer was attacked on the Metro Bus platform. Gunfire was exchanged. And there were -- there were several casualties. The incident is over, the scene is secure and -- most importantly -- there's no continuing threat to our community," he said.
"There were a number of people that fled and there were some erroneous reports," he added.
The FBI is leading the investigation into the attack.
While sources told ABC News there was no known motive, they added that there was no obvious connection to terrorism. Those same sources stressed it's still early in the investigation.
The medical examiner in Washington did not immediately respond to a request for a comment.
Pressed on reports on whether an officer died, Kusse said he couldn't release those details as the investigation is ongoing.
"I don't want to compromise the integrity of that process right now," he said.
"I'm not confirming or denying those particular reports right now the investigation is ongoing. And I do promise to get back as soon as possible, with further details but I can't release those right now," he said.
Pressed for information about the assailant, he added, "We are not actively looking for another suspect."
Across town on the National Mall, Capitol Police officers on motorcycles led a ceremonial procession, passing by saluting law enforcement officers from Washington’s Metropolitan Police Department, the Pentagon Force Protection Agency and other police departments, to honor the Pentagon police officer reportedly wounded earlier -- though the Pentagon wouldn't confirm his injuries.
The Pentagon was placed on lockdown Tuesday morning after the incident at the Pentagon Transit Center involving a stabbing and a shooting, according to a separate U.S. official earlier.
The lockdown was later lifted and the Pentagon reopened, the Pentagon Force Protection Agency said shortly after noon.
The Pentagon had no details regarding the assailant's motivation Tuesday afternoon, but Kusse said they will review the results of the investigation before making a determination on whether security measures should change.
"Every time an incident occurs, whether it's here or anywhere else across the nation or in the world, we do after actions on those we examine them, we look for things that we can do to improve. But right now, again, it's still pending, we will certainly, as this investigation concludes, take another look at any measures," he said.
Defense Secretary Lloyd Austin and Gen. Mark Milley were not in the Pentagon at the time of the incident. They were both at the White House for their weekly meeting with President Joe Biden and they were all aware of the ongoing situation.
Kirby said Tuesday afternoon that Austin was back in the Pentagon and had a chance to visit the Pentagon police operations center to check in and express his gratitude for their work.
ABC News' Libby Cathey contributed to this report.