Around 12,000 US service members, including from the Marines and Navy, will join South Korean troops.
Military observers, in fact, took notice recently when parasites were discovered in the stomach of a North Korean soldier who defected to South Korea, suggesting even front-line troops are enduring awful conditions as they operate near the DMZ.
A U.S. B-1B bomber on Wednesday joined large-scale U.S.
B-1Bs flyovers have become an increasingly familiar show of force to North Korea, which after three intercontinental ballistic missile tests has clearly moved closer toward building a nuclear arsenal that could viably target the USA mainland. Yet the Air Force claimed that the drills were "not in response to any incident or provocation" and pointed out that the USA and South Korea carry them out every year.
It is increasingly common for the USA to deploy B-1B bombers over South Korea to underline military superiority against North Korea.
The South China Morning Post quotes Li Jie, a Beijing-based military expert, as saying the drills were done specifically to send a message to Donald Trump.
South Korean President Moon Jae-in will visit China next Wednesday for a summit with his counterpart Xi Jinping, Seoul's presidential Blue House said.
But Chinese leaders have criticised the nuclear build-up of Kim Jong-Un's regime as well as lambasting the United States and South Korea for escalating tensions.
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.
North Korean defectors claim that a mysterious "ghost disease" is ravaging people living near the country's nuclear test site, causing ill-health and death.
Paintings from North Korea's most celebrated artists are being sold at high prices, with some works priced in the tens of thousands of dollars, according to the report. Additional major sanctions will be imposed on North Korea today.
Feltman's trip - the first by a UN diplomat of his rank since 2010 - comes less than a week after North Korea test-fired a new ballistic missile said to be capable of reaching the United States.