Emirates flight 176 from St. Petersburg, Russia to Dubai caught fire while still on the ground prior to departure. It’s being reported that the fire was in an engine of the Boeing 777, and that passengers were evacuated. The flight currently shows a 3 a.m. estimated departure time, four hours late, but that seems.. optimistic?
Judging from video of the incident I’d have to speculate that it’s not one of the plane’s engines but its auxiliary power unit.