A technical snag in an engine grounded a Mumbai-Delhi IndiGo flight shortly before take-off here on Saturday evening, official sources said.

The incident happened when the IndiGo flight 6E-248 was preparing for take-off from the Chhatrapati Shivaji Maharaj International Airport around 10.30 p.m.

After switching on the take-off power, the captain noticed the snag.

The crew and passengers on board reportedly heard a loud noise and saw some flashes of light from the left engine, but officials denied reports of an engine fire.

As a precautionary measure, the flight captain decided to abort the take-off and returned to the bay where the passengers deboarded.

All passengers and aircraft are safe and the aircraft has been grounded for technical inspection.

The IndiGo Flight Safety Department is conducting preliminary investigation, an official said.

The matter has been brought to the notice of the Director General of Civil Aviation, the sources said.