Beginning Wednesday, people in northeast Nebraska will see an increased presence of military aircraft over the next week.

The Iowa National Guard is conducting a simulated regional emergency response exercise that also includes Nebraska, Missouri and Kansas Guard units.

About 300 Nebraska Guard personnel will participate in the Vigilant Guard '09 exercise.

An additional 1,000 soldiers and airmen from the Iowa National Guard and another 250 soldiers and airmen from Kansas and Missouri will participate.

Exercise elements will include a simulated train derailment in both Kansas and Iowa, a response to a foreign animal disease and support to state agencies due to a manmade biological release.

The purpose of the training event is to identify gaps that may exist between civilian, governmental and military response organizations from different states.