Flights at Newark Airport were grounded for three hours Saturday after a plane made an emergency landing and passengers had to be evacuated, airport officials and witnesses said.

“Due to an airport emergency there are currently no arrivals nor departures from Newark Airport,” the airport tweeted around 8:30 am.

Passengers at Newark said the United Airlines flight had taken off from LaGuardia Airport and was headed to Houston when it was forced to make an emergency landing for reported hydraulics issues.

It apparently is #UA2098 from LGA to Houston that diverted to Newark. pic.twitter.com/snwgMJXt8h

— Jan-Hendrik Fiedler (@FlyingFan1) June 29, 2019

Others at Newark described chaos on the runway.

“Plane landed with hydraulic issues,” said witness @eckert_david on Twitter. “Emergency vehicles all over the runway. Passengers on runway.” 

The exact cause of the landing was not immediately clear.

“All I know is that 10 minutes after takeoff we weren’t getting much altitude, we were just circling around northern New Jersey and not going anywhere,” passenger John Murrary told CNN. “That’s when we landed … at Newark.”

Everyone was evacuated safely, while incoming flights were reportedly diverted to other airports. 

The airport was reopened about an hour after the emergency landing, though flights were still expected to be delayed.