Trains on the Washington area Metro system were ordered to bypass the huge Defense Department headquarters after the object was discovered in the station at 7:15 a.m., said Chris Layman, spokesman for the Pentagon police force.
"Someone spotted some lights that were was blinking in a trash can," Layman said. "We took it seriously, it was called a 'suspicious object' and they came and x-rayed and inspected the item."
Trains were forced to pass through the station without stopping, meaning passengers had to get off at a different station and walk, or take a bus back, to the building. The Pentagon is also a major transit point for a number of area buses, and people lined up by the hundreds as police investigated.
"We determined it was a battery-operated Christmas ornament," Layman said.
An "all clear" was issued at 8:44 a.m.