NSA headquarters
The National Security Agency's headquarters in Fort Meade, Maryland Saul Loeb/Agence France-Presse via Getty Images

Updated at 2:38 p.m.:

The Federal Bureau of Investigation in Baltimore said Monday it is investigating the shooting incident at the gate of the National Security Agency headquarters at Fort Meade in Anne Arundel County, Maryland.

"The shooting scene is contained, and we do not believe it is related to terrorism," said FBI Baltimore spokeswoman Amy Thoreson said in a statement Monday. "We are investigating with NSA Police and other law enforcement agencies."

Updated at 11:19 a.m.:

Two cross-dressed men in a stolen SUV tried to ram the main gate at the National Security Agency's headquarters Monday morning in Fort Meade, Maryland. A police officer shot and killed one of the men and seriously injured the second, WJLA news station in Washington, D.C., reported. A motive for the gate-crashing incident is unknown, and the identities of the two men have not yet been released.

Original story:

A shooting was reported near the National Security Agency's headquarters in Fort Meade, Maryland, early Monday. At least two people were treated for injuries at one of the gates of the sprawling building near Baltimore, media reports said.

Photos posted on social media by local news stations showed two damaged vehicles near one of the gates of the headquarters, and an emergency response worker appeared to be loaded into an ambulance. Local news station WTTG in Washington reported that a car tried to ram the gate leading into the complex.

The facility in Anne Arundel County houses the NSA and other federal agencies. About 11,000 military personnel and another 29,000 civilian employees are on site, the NSA's website says.

This is a developing story.