Tom Vanden Brook, and Doug Stanglin

USA TODAY

A security forces team conducting a routine inspection at Andrews Air Force base was mistaken for an active shooter Thursday, prompting a lockdown of the facility just as a scheduled training exercise to deal with such an emergency was about to begin, officials said.

The report prompted officials to put the base on lockdown for almost two hours and order personnel to remain in place.

Col. Brad Hoagland, commander of the base outside Washington, D.C., that is home to Air Force One, said on Twitter that "a real-world active shooter situation at the (base) medical facility were miscommunicated before the exercise was able to begin."

He said the confusion stemmed from the "misidentification" of the security forces emergency services team that was conducting a routine inspection of the facilities.

On the positive side, Hoagland applauded the "quick reaction of our first responders."

Vice President Joe Biden was scheduled to leave from Andrews on Thursday morning, but his trip was delayed by the lockdown, the Associated Press reported.

The vice president’s office said he was waiting out the delay at his residence at the Naval Observatory in Washington.

Biden was due in Columbus, Ohio, for a midday campaign event for former Gov. Ted Strickland, who is running for Senate.

President Obama was last at the base Wednesday night when he returned from a trip to Ottawa, Canada.