A flock of birds may have been the cause of panic in Washington, sending the White House and Capitol into lockdown, according to officials.

The alarm bells were sounded on Tuesday, with reports of an aircraft violating the tightly controlled airspace around the president’s official residence.

As a precautionary measure, there were evacuations around the city, and reporters were told they could not leave the White House press briefing room until the situation became clear.

As it turns out, there was no wandering plane. And, instead, officials believe that “a flock of birds or a weather balloon” may have triggered North American Aerospace Defense Command (NORAD) systems, according to a spokesperson for that agency.

The Secret Service has said that the White House went on lockdown “due to a potential violation of the restricted airspace in the National Capital Region.”

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Capitol Police, meanwhile, said on Tuesday that they were “tracking an aircraft that poses a potential threat to the Capitol Complex”.

But, ultimately, NORAD said “no aircraft” had been sighted.