The sparse expanses above Alaska are a little more crowded this month as nearly 200 military aircraft are taking part in an annual training exercise.

Nearly 6,000 military members from all four branches of the military are taking part in Northern Edge 2015, which includes naval exercises in the Gulf of Alaska and some ground troops.

The U.S. Pacific Command exercises test the readiness of the nation's troops, and officials say it isn't in response to any increased tensions with any other nation.

Northern Edge is normally held every two years, but this is the first exercise since 2011. The government shutdown, or sequestration, forced the cancellation of exercises in 2013.