WASHINGTON

A flight arriving at Reagan National Airport was met with an emergency response on Tuesday after a reported security threat prompted authorities to halt airport operations for more than an hour, according to authorities.

United Airlines flight 512 landed at around 11.30 am local time (1630GMT) and stopped on an adjacent runway, away from the terminal, in response to the threat, the airport said on US social media company X.

Runways remained closed until passengers were "safely" offloaded and bused to the terminal. Runways reopened at 12.50 pm.

Metropolitan Washington Airports Authority police are conducting a "thorough investigation" with assistance from multiple law enforcement partners.

"Several flights were diverted to other airports during the runway closure. People meeting passengers or flying this afternoon should expect delays and check with their airline for updated flight information," it added.

Transportation Secretary Sean Duffy said the flight from Houston to Washington, DC received "a bomb threat."

"The flight landed safely at DCA, passengers were evacuated, and law enforcement conducted a full search of the aircraft," Duffy said on US social media company X, adding that the FAA received the all clear and operations have resumed.