"Due to security" was the FAA's National Airspace System Status explanation for issuing the ground stop for DCA. The ground stop was issued at 1:43 p.m. on Wednesday and was scheduled to stay in place until 3 p.m. The probability of an extension was "medium," according to the FAA.

The Federal Aviation Administration said it is "aware of a reported security issue on an aircraft at Reagan Washington National Airport" near Washington, D.C.

Air traffic control audio shows the communication between the tower and pilots during the bomb threat. The ground stop contributed to flight delays.

Flights operations at Ronald Reagan Washington National Airport airport, which were halted due to a bomb threat on a United Airlines flight, were resumed from main runway at 12:50 pm.

The Federal Aviation Administration says it halted all flights at Ronald Reagan Washington National Airport for a time Tuesday because of a security threat.

An unconfirmed report of a bomb threat has led to a ground stop at Ronald Reagan National Airport outside Washington, D.C.

Flights resumed in the early afternoon after passengers were safely taken off a plane that arrived from Houston, the airport said. The F.B.I. said “no hazards” were found.

Flights in and out of Ronald Reagan Washington National Airport near Washington resumed on Tuesday after flying was halted due to a bomb threat on a United Airlines Holdings Inc. jet.