“This mission… demonstrates the United States’ ability to conduct long range, precision strikes quickly and at will,” said a statement from the United States Forces Korea, a division of the US Strategic Command under the Department of Defense.

While it is unclear if US stealth bombers had been used in previous military drills with South Korea, this was the first time the military announced their use, the Associated Press reported.

The two bombers, capable of carrying both conventional and nuclear weapons, left the Whiteman Air Force Base in Missouri and flew more than 6,500 miles (10,461 km) to the Korean Peninsula where they dropped the inert munitions on an island range facility off the western coast of South Korea, and then returned to the United States “in a single, continuous mission,” according to the statement.

The flight was "intended to demonstrate very clearly the resolve of the United States to deter against aggression on the Korean Peninsula, and our strong commitment to the US alliance with South Korea," a senior defense official told CBS News.

The point was underscored in a phone call Wednesday night between US Secretary of Defense Chuck Hagel and South Korean Defense Minister Kim Kwan-jin.

"Secretary Hagel and Minister Kim reaffirmed the strength of the alliance, which has been, and continues to be, instrumental in maintaining stability on the Korean Peninsula,” Pentagon Press Secretary George Little said in a statement.

The bombing mission comes in the midst of escalating tensions between the United States and North Korea.

Earlier this month a spokesman for the North Korean Foreign Ministry threatened a pre-emptive nuclear strike against the United States after the United Nations Security Council approved sanctions in response to a third nuclear test by North Korea in February.

The US military announced earlier this month that it would strengthen its missile defenses in response to threats from North Korea.

“The United States is steadfast in its alliance commitment to the defense of the Republic of Korea, to deterring aggression, and to ensuring peace and stability in the region,” said the statement from the United States Forces Korea released Thursday.