WASHINGTON — The Defense Department said Monday evening that suspicious packages had received packages at military installations in the Washington, D.C., region, and were under investigation.

In a statement, the department said “we are tracking the delivery of suspicious packages to multiple military installations in the National Capital Region.”

In the statement, Army Lt. Col. Michelle Baldanza said “this incident is currently under investigation.”

She said the Pentagon was referring all queries to the FBI.

In a statement, the FBI’s Washington field office said the bureau responded to multiple government facilities Monday “for the reports of suspicious packages.” The bureau said each package was collected for further analysis. The precise number of packages involved could not be learned. According to media accounts, the packages may have been received at as many as six sites.

The sites included Joint Base Anacostia-Bolling in the District of Columbia and at Fort Belvoir in Virginia, according to the accounts.

In addition, an NBC news report indicated that “similar” packages were located at mail processing facilities for both the CIA and the White House.

No injuries were reported, and information about the contents of the packages was not immediately available.

It was not clear what led authorities to deem the packages suspicious. Most or all of the installations involved have means to detect possibly hazardous materials within packages.

According to authorities, at least one of the packages did contain black powder. Black powder is an ingredient of some explosive devices.

In a statement, an Army spokesman said a suspicious package was received at the National Defense University at 8:30 a.m. Monday on the grounds of Fort McNair.

Mike Howard, a spokesman for Joint Base Myer-Henderson Hall, said the building was evacuated immediately and the area was cordoned off.

Fort McNair is in southwest Washington, west of Nationals Park.

Shortly after noon, according to Howard, an Army explosive ordnance disposal unit from Fort Belvoir “confirmed the package tested positive for black powder and residue.

He said an X-ray indicated what was suspected to be a type of fuse attached.

Howard said the package was “rendered safe,” and no injuries were reported.

He said the premises were later cleared for re-entry.

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