A United Airlines flight traveling from Chicago O’Hare International Airport to Minneapolis-St. Paul International Airport made an emergency landing in Madison, Wisconsin after a passenger allegedly attempted to gain access to the cockpit.

The Boeing 737-924(ER) aircraft (registration N69818), operating as United Flight 2005, diverted to Dane County Regional Airport following what authorities described as a level 4 security incident. During the incident, the flight transmitted squawk code 7500, an internationally recognized emergency signal for a hijacking.

Law enforcement personnel on board subdued the passenger before the aircraft landed in Minneapolis early Saturday morning. The flight carried 147 passengers and six crew members with no reported injuries. United Airlines stated that the flight “landed safely in Madison … to address a security concern with an unruly passenger.”

Reports indicated the passenger allegedly engaged in verbal outbursts in Russian and caused a struggle on board. Federal authorities responded at Dane County Regional Airport, where the passenger was detained.

Squawk code 7500 allows pilots to contact air traffic control discreetly, typically involving security forces that may include military escorts or additional authorities upon arrival. The aircraft resumed its journey to Minneapolis after landing in Madison and arrived early Saturday morning. Dane County Regional Airport operations were restored following the passenger’s arrest.