WASHINGTON (WASHINGTON POST) - The US Defense Department said it was looking into the arrival of suspicious packages at military installations in the Washington region.

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 Federal Bureau of Investigation.

Media reports indicated that packages were found at Joint Base Anacostia-Bolling in the District of Columbia and at Fort Belvoir.

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.

In addition, one source with knowledge of the investigation said it was unclear, at least in the initial stages of the inquiry, whether the packages were actually capable of exploding.

At least one of the packages reportedly did contain black powder, an ingredient of some explosive devices.

That package was received in the morning at the National Defense University at Fort McNair, in southwest Washington, near Nationals Park.

The building was evacuated, CNN said, quoting Gen Michael Howard, the commander of the Military District of Washington.

According to CNN, Howard said a bomb disposal unit from Fort Belvoir confirmed the package "tested positive for black powder and residue". It was rendered safe, and no injuries were reported.