A plane carrying first lady Melania Trump returned to Joint Base Andrews shortly after takeoff on Wednesday after a "mechanical issue" caused smoke and the smell of something burning.

A spokeswoman for Trump said she is "fine" after the "minor mechanical issue" with her aircraft, and that she is eager to get to Philadelphia for a planned event with her Be Best campaign, which advocates against bullying and drug use.

Health and Human Services Secretary Alex Azar, who is accompanying Trump on her trip and was also on board the flight, is also fine, the first lady's office said.

Reporters traveling with her on the plane said a burning smell filled the cabin about 10 minutes after takeoff, and "a thin haze of smoke" was visible. A member of the flight crew passed out damp washcloths for passengers to hold over their faces for the smell, and the smoke dissipated before the plane landed safely back at Andrews. A member of the first lady's staff told press that the incident was due to a "mechanical problem."

Both Trump and Azar have boarded a second plane.

Trump is expected to meet with families affected by the opioid crisis in Philadelphia on Wednesday, as well as tour a neonatal intensive care nursery.