Officials say a flight bound for Newark, New Jersey, never made it off the runway after engine troubles forced the plane to abort takeoff at San Francisco International Airport

San Francisco airport duty manager Nancie Parker said the craft was towed back to the gate and there were no reports of injuries. Parker says witnesses reported seeing flames, but she could not confirm that and United wouldn't comment.

A passenger onboard said he heard a very loud bang and then saw fire trucks pull up. Chris Archer said he didn't see any fire, but felt the plane veer to the left. He said the atmosphere on board was tense and quiet.

United says it's working to get passengers on other flights to Newark.