Madison, Wisconsin – A United Airlines flight from Chicago to Minneapolis was forced to make an emergency landing on Friday night after a passenger allegedly tried to breach the cockpit.

The incident occurred shortly after United Airlines flight UA2005 took off.

The suspect was reportedly a Russian citizen, according to the aviation portal PYOK.

The Boeing 737 was already cruising at about 30,000 feet en route to Minneapolis when the pilots suddenly changed course and initiated an immediate diversion to Madison, Wisconsin.

Jennifer Lopez Jennifer Lopez changes "infinity" tattoo following divorce from Ben Affleck

According to reports, the man caused trouble even before takeoff, reacting aggressively after flight attendants asked him to remain seated while the aircraft was taxiing.

In the air, the situation escalated. The passenger allegedly threatened fellow travelers and crew members before charging at the cockpit door.

According to PYOK, the pilots then placed the cockpit in lockdown mode and reported a so‑called "Level‑4 incident" – the highest alert level in international aviation.

This is triggered when a passenger attempts to enter or take over the cockpit.

The threat was apparently taken so seriously that United Airlines sent a warning to the airline's other aircraft.

China China building sprawling launchpads close to nuclear missile silos, new report reveals

Pilots were instructed to secure their cockpits in case it was a coordinated attack.

Several off‑duty police officers were on board the aircraft. Together with the crew, they managed to subdue the man and keep him restrained until landing.

After the safely landing in Madison, the suspect was taken into custody by authorities. No injuries were reported.