Witnesses said the two helicopters exploded into flames after plummeting to the ground on a military base following the collision. Five bodies were pulled from the wreckage, the reports said.
Officials would not confirm the accident, which occurred following exercises at the Santa Lucia air base near Mexico City, according to Mexican radio.
According to reports, both helicopters were Russian-made.
In mid-October two Mexican military helicopters crashed in separate incidents, leaving five people dead and three injured.