More than 1,000 troops, five ships and seven aircraft are taking part in the exercises, which include simulated operations to disarm rebel groups and rescue civilians from a battle zone.
Military authorities say the drills _ which began Thursday _ are routine.
But Crimea is a focus of tension between Russia and Ukraine. It is home to a Russian naval base in addition to a Ukrainian one, and Moscow has objected to Yushchenko's plans to evict the Russian navy when the lease agreement expires in 2017.
Yushchenko has expressed concern about Russia's intentions after its war with Georgia last year and has called for major funding increases for Ukraine's cash-strapped armed forces.