In a rare incident, three planes of three foreign airlines, carrying hundreds of passengers, came perilously close in the Delhi flight information region and collisions were averted after multiple auto generated warnings and intervention from ATC, an official said Friday.

The Aircraft Accident Investigation Bureau (AAIB) has started a probe into the incident, which happened on December 23. Flights of Dutch carrier KLM, Taiwan's Eva Air and the US-based National Airlines were involved in the incident, the official said.