United Airlines is operating regional flights using partner airlines under their United Express brand. A runway at Newark Liberty International Airport was shut down after a regional flight bound from Newark to Pittsburgh had to return today the airport shortly after its departure Thursday morning. This was due to a smoke condition in the aircraft, officials said.

The airplane, operated by Republic Airlines flight UA4890 operating as United Express, was evacuated and buses were called to pick up the passengers, according to the Federal Aviation Administration.

Republic Airlines carried 27 passengers and four flight crew members. The pilot was able to land the plane without incident. Maintenance crews were inspecting the aircraft and passengers were scheduled to board a different flight to Pittsburgh.

Delays were reported at Newark airport in New Jersey, USA, as authorities investigated.