A passenger plane was forced to make an emergency landing in the US state of Oregon on Friday after its window exploded in mid-air, the BBC reported.

An Alaska Airlines Boeing 737 Max 9 returned to Portland, California 35 minutes after takeoff when part of its structure collapsed.

The company said the 177 passengers and crew on board “landed safely”.

The company continued in a statement: “While this type of event is rare, our flight crews are trained and prepared to manage the situation safely.” “We are investigating what happened and will share more information as it becomes available.”

According to Federal Aviation Administration data, the new MAX 9 was delivered to Alaska Airlines in late October and certified in early November.

The airline said it was “temporarily grounding” all 65 of its 737 MAX 9 planes.

Boeing said it was aware of the incident and was “working to gather more information,” according to the BBC.

“Each aircraft will return to service only after full maintenance and safety inspections have been completed,” Alaska Airlines CEO Ben Minicusi said in a statement.

Minicucci praised the efforts of the six crew members on board, which, according to flight tracking data, had climbed to an altitude of 16,000 feet (4,876 meters) when it began an emergency descent.

Pictures circulating on social media show a gap that allows a view of space from inside the plane after the plane's window and part of the side wall were damaged.

Exterior photos of the plane appear to show the rear exit door in the middle of the cabin separated from the plane, Flightradar24 reported in a post on its website.