A lockdown on the Pentagon prompted by an attack on a law enforcement officer was lifted Tuesday as authorities said the immediate threat has been resolved.

Pentagon Police Chief Woody Kusse would not confirm how many people were injured in the attack, nor details on the status of the officer or the suspect, but said there were "several casualties" following the Tuesday morning incident.

The attack took place on the Metro bus platform near the Pentagon. "Gunfire was exchanged and there were several casualties," said Kusse. The cause of the casualties remains unclear.

Multiple reports said the officer was fatally stabbed on the platform and the suspect was killed but Kusse declined to confirm or deny those details when pressed by reporters.

He said the scene is now secure, "and there is no continuing threat." He added that police are "not actively looking for another suspect at this time."

The police chief pledged to provide additional details as soon as they become available.

The Pentagon went into lockdown after reports of shots fired at the nearby transit station that led to “multiple patients" needing medical care.

The Arlington County Fire Department separately said it was responding to "multiple patients" at the Pentagon metro station, but said no further information would be provided on the statuses of patients.

The Pentagon Transit Center is a major transportation hub near the Pentagon and is used by multiple bus lines and includes a metro train stop.