UPDATE:  The National Transportation Safety Board says one person has died after a Southwest Airlines plane with engine failure made an emergency landing in Philadelphia.

PREVIOUS STORY: A Southwest Airlines plane made an emergency landing Tuesday in Philadelphia after the crew reported damage to one of the aircraft's engines, the fuselage and at least one window, federal aviation officials said.

The Federal Aviation Administration did not immediately detail what happened on board Southwest Flight 1380, which was flying from New York's LaGuardia Airport to Dallas Love Field in Texas when it was diverted to Philadelphia International Airport, according to the airline.

But reports on social media indicated the plane depressurized mid-flight when a piece of an engine apparently flew into a window, shattering it. Images of the plane showed an engine appearing exposed and shredded. NBC News could not immediately verify the reports.

"This appears to be what aviation officials call an uncontained engine failure," NBC News aviation specialist Jay Blackman said. "Engines are designed, when they fail, to fail inside the engine cowling. But in this case it looks like it pierced the cowling, and not only the cowling, but it pierced part of the fuselage.”

Philadelphia airport officials said the flight was diverted due to an "operational event" but did not give any more information.

Southwest said there were 143 passengers and five crew members aboard the Boeing 737. Condition of the passengers was not immediately known.

"We are in the process of gathering more information," Southwest said in a statement. "Safety is always our top priority at Southwest Airlines, and we are working diligently to support our customers and crews at this time."

According to the Philadelphia airport, the flight was "diverted to PHL because of an operational event" and landed safely. Passengers could be seen exiting through a mobile stairway before being bussed to a terminal.

The FAA issued a ground stop for the Philadelphia airport and told passengers to expect delays. The agency said it was investigating the incident.

The National Transportation Safety Board will lead the investigation into what happened, the FAA added.

This is a breaking news story. Please check back for updates.