A Southwest Airlines flight from Chicago to Newark was diverted to Cleveland on Wednesday morning after a window pane cracked midflight.

Passengers onboard Flight 957 reported hearing a loud pop as a large crack formed in the window's outer pane on the Boeing 737-700 aircraft.

The incident comes two weeks after a high-profile accident in which an engine failure on Southwest Flight 1380 sent debris into the fuselage and caused a window to blow out. The passenger sitting next to it was partially pulled out the window on that April 17 flight and later died from her injuries.

On Wednesday, Southwest said the Flight 957 landed "uneventfully" in Cleveland and that the aircraft has been taken out of service for an inspection.

"Our local Cleveland employees are working diligently to accommodate the 76 customers on a new aircraft to Newark," the Dallas-based carrier said in a statement.

A Southwest spokeswoman said further investigation is needed to determine what caused the crack.

No passengers were reported injured in Wednesday's incident, but the frightening ordeal did send passengers scrambling away from the window and reminded some of the Flight 1380 accident.

"It made you nervous because something like this just happened," passenger Paul Upshaw of Chicago, who was about two seats from the window, told The Associated Press. "We didn't know if it was going to crack open."

On my way to NJ for work and #Southwest957 gets a window crack. Only outside crack so we're all safe. On our way to NJ in new plane. Thanks to the @SouthwestAir crew and pilots for handling it professionally. pic.twitter.com/CB4s7SQtS3 — AA (@Dro_AA) May 2, 2018

Southwest said the Boeing 737-700 aircraft maintained cabin pressurization and that an emergency was not declared. The windows have three layers — an outer pane that is the primary pressure load carrier, a middle pane that serves as a structural fail-safe if the outer pane fractures and a non-structural interior pane that can be touched from inside the cabin.

Spokeswoman Brandy King said the pane has been replaced before and was last inspected in April.

Aviation experts said window cracks are rare and the windows are periodically polished to remove tiny cracks that form in the acrylic windows from exposure to chemicals and the sun. The multi-layer design is meant to help prevent a window blowout.

"My suspicion is it was the outside part but the frame held and kept it in place. It performed as intended," Richard Healing, a former National Transportation Safety Board member who now leads Air Safety Engineering, told Bloomberg News.

Southwest Flight 957 left Chicago's Midway Airport at 8:36 a.m. and landed at 10:46 a.m. at Cleveland's Hopkins International Airport, according to flight-tracking service FlightAware.

The April 17 accident involving Flight 1380, the first U.S. airline accident to involve a passenger death in nine years, has cast a spotlight on airline safety and led the Federal Aviation Administration to order more frequent inspections of engine fan blades.

The National Transportation Safety Board is still investigating the April 17 incident but said it found signs of internal cracking on a fan blade that broke off from the plane's engine, leading to damage to the engine casing and aircraft fuselage.

Southwest said it's seen a slowdown in bookings since the incident and estimated it could cost the company $50 million to $100 million.

Material from Bloomberg News and The Associated Press was used in this report.