The US Capitol was briefly evacuated after a parachute demo into Nationals Park for a baseball game.

In an email to press, the US Capitol police initially said they were tracking an aircraft that poses a probable threat to the Capitol Complex, and issued an evacuate of the area around 6:30 p.m.

The USCP later said there was no threat at the Capitol after it was evacuated. Heather Caygle reported that the plane failed to respond to communication and that the plane was evacuated.

The Capitol was evacuated out of an abundance of caution.

Two people familiar with the matter say that CNN's Mike Valerio first reported that it was a single-engine aircraft carrying parachutists. Valerio said that the flyover was not coordinated appropriately.

The Golden Knights, the US Army's official aerial parachute demonstration team, were performing a demo at Nationals Park, a mile away from the Capitol, while the plane was taking off. The alert was issued because it was circling inside restricted airspace near the Capitol.

According to the AP report, the plane, a De Havilland Twin Otter, remained clear of the prohibited airspace over the Capitol Building and other government complexes at all times.

The demo was not properly coordinated prior to the event.

Nancy Pelosi slammed the FAA for failing to notify the USCP of the pre-planned flyover of the stadium, which caused unnecessary panic for lawmakers and staff.

The Federal Aviation Administration's apparent failure to notify Capitol Police of the pre-planned flyover Nationals Stadium is outrageous and inexcusable.

Congress looks forward to reviewing the results of a thorough after-action review that determines what precisely went wrong today and who at the Federal Aviation Administration will be held accountable for this outrageous and frightening mistake.

Insider requested more details from the USCP, but they did not respond immediately.