Last week North Korea tested what it claimed was its most powerful intercontinental ballistic missile that could reach the U.S. mainland.
"Through the exercise, the South Korean and US Air Forces have demonstrated the alliance's strong will and capability for strong retaliation against North Korea's nuclear and missile threats", the JCS said.
The South Korean army is reportedly on course to launch a combat unit consisting of drone bots sometime next year, in a move that signals a new era of drone bots in the military.
North Korean leader Kim Jong-un toured a powdered potato factory in Ryanggang Province near the border with China on Wednesday, well away from the state-of-the-art US fighter jets that are buzzing his southern border.
A U.S. B-1B bomber on Wednesday joined large-scale U.S.
North Korea regularly threatens to destroy South Korea, the United States and Japan.
It also labeled Trump, who has threatened to destroy North Korea if the United States is threatened, "insane".
North Korea typically uses strong language when commenting on U.S. "Even if a war erupts on the peninsula, it is South Korea, Japan and the U.S. bases in the Asia-Pacific that will likely be priority targets for North Korea".
Defectors tell of deformed babies, deaths and lingering disease for those living near North Korea's nuclear testing zones.
The exercises are specifically focused on the threat from North Korea, as USA and South Korean forces are training to strike North Korean nuclear and missile sites, as well as its mobile missiles.
North Korean Vice Foreign Minister Pak Myong Guk met Feltman on Wednesday in the North Korean capital, Pyongyang, and discussed bilateral cooperation and other issues of mutual interest, KCNA said.
President Donald Trump has been tightening the screw on North Korea, ramping up sanctions and urging other countries to sever trade links with Kim Jong Un's regime.
The US and South Korea kicked off the five-day war games - called Vigilant Ace - on Monday, with more than 200 aircraft, which have been conducting mock attacks on North Korea in different war scenarios. -South Korean military exercises that it claims are preparations for an invasion of the reclusive country.
The US responded to North Korea's latest missile launch with a simulated bomb run from a B-1B Lancer bomber and an F-22 in a marked escalation in military signaling.