New photos of the Boeing 777 engine that failed show where a blade snapped off inside

• Photos show the damage to a Boeing 777 engine that failed soon after takeoff in Colorado.
• United Flight 328 landed safely after the failure of the Pratt & Whitney engine.
• US investigators released the images and said the damage was consistent with metal fatigue.

New photos show a Boeing 777 engine that failed shortly after takeoff, including a fan blade that snapped.

The images were released by the US National Transportation Safety Board late Monday. They show the United Airlines plane that was forced to turn back and land in Denver on Saturday.

An image of the Pratt & Whitney PW4000 engine shows where a fan blade snapped and damage to the blade beside it:

Investigators on Monday said most of the damage to the plane was confined to a single engine.

They said their examination showed that two of the blades were fractured and part of one was embedded in the ring around the edge of the engine.

They said one of the fractured blades snapped, most likely hitting and damaging the other.

The NTSB's chairman, Robert Sumwalt, said at the Monday briefing that the damage to the engine seemed "consistent with metal fatigue."

The NTSB cautioned that it had done only a preliminary inspection and said it was not yet drawing conclusions as to what went wrong with the plane. A full investigation is underway.

Another photo shows the plane after the flight, with its engine cover separated:

Investigators also shared photos of damage to the plane's body. They described the section of fuselage as noncritical to flight.

The NTSB said the plane was carrying 229 passengers and 10 crew members. No injuries were reported.

Video footage captured during the flight showed the broken engine on fire.

And photos show that debris from the plane landed in neighborhoods near the airport in Colorado:

The NTSB said it was analyzing the plane's cockpit voice recorder and flight-data recorder.

The NTSB's investigations into such incidents typically take more than a year.

United Airlines has suspended its use of all 24 of its 777 planes with that engine that it has in service. The airline also has 28 of the planes with that engine in storage.

Other airlines that fly the model - Korean Airlines, Asiana Airlines, Japan Airlines, and All Nippon Airways - are suspending their active 777 planes with the engine too.

Boeing said it supported the move, recommending that airlines suspend their use of Boeing 777s with that engine. It said 69 were in use around the world, with more in storage.

The head of the US Federal Aviation Administration on Sunday said he was requiring "immediate or stepped-up inspections" of the planes with that engine.

Reuters reported that Pratt & Whitney said it was coordinating with regulators.