The United States has begun operating two types of radar-evading aircraft, a bomber and a fighter, for the first time together in the Pacific in Guam.
The pairing follows United States suspicions that North Korea is planning to test fire a long-range missile.
North Korea announced this week that it plans to launch a satellite on a rocket as a part of a peaceful space programme.
This comes a fortnight after the US signing a deal to push ahead with the relocation of 8000 marines to Guam by 2014.
Guam is a US territory and its Andersen Air Force Base is a major operational hub for U.S. forces in the Pacific.
US Air Force General Howie Chandler says the aircraft deployment is not designed to deliver a political message, but to showcases an element of advanced U.S military power in the Pacific at a time of tension over North Korea.