Trump has said he spoke with Chinese President Xi Jinping about Pyongyang's "provocative actions", and he vowed that additional major sanctions will be imposed on North Korea.
Some 230 aircraft and 12,000 personnel from the US and South Korea are participating in the weeklong exercise, according to a US Air Force statement.
The five-day Vigilant Ace drill - involving some 230 aircraft including F-22 Raptor stealth jet fighters - begins on Monday, five days after the North test-fired an intercontinental ballistic missile believed capable of hitting the United States mainland in a fresh challenge to President Donald Trump.
"Should the Korean peninsula and the world be embroiled in the crucible of nuclear war because of the reckless nuclear war mania of the U.S., the USA will have to accept full responsibility for it", North Korea's state-run Korean Central News Agency said Saturday, citing a statement by the Ministry of Foreign Affairs.
Since July's launch of the Hwasong-14, its first long-range intercontinental ballistic missile (ICBM), North Korea analysts have been looking for signs the isolated country has developed precise guidance systems, reliable and powerful rocket engines, and a re-entry vehicle capable of protecting a nuclear warhead as it speeds toward its target.
Graham expressed confidence in the Trump administration's ability to manage the growing conflict with North Korea.
The missile is said to have flown almost 2,800 miles high and for a distance of more than 600 miles.
"What is clear is that every time he conducts a missile launch, a nuclear test, he gets better", McMaster told Baier, "Whether it's a success or failure isn't as important as understanding that over the years he's been learning from failures, improving, and thereby increasing his threat to all of us".
The Rodong Sinmun commentary said the aerial wargames show "the enemies' moves to start a nuclear war have reached a unsafe stage".
"It's insane to send spouses and children to South Korea, given the provocation of North Korea".
The Hwasong-15 is believed to have reached the highest altitude ever recorded by a North Korean missile. "The combination of those two things means it really is a new, more capable missile". "However, the quake could have been caused by geological changes created from the recent nuclear explosion", said an agency official who asked not to be named.