The USS Ronald Reagan aircraft carrier arrives in the South Korean port city of Busan on October 21, 2017.
The first payoff is that the agreement offers assurances from Seoul that it recognizes China "strategic position in the region".
The drills began in waters off South Korea's eastern coast.
November 11: United States and South Korea on Saturday started joint naval four-day drills to warn the North Korea.
"The strike force plans to conduct air defense drills, sea surveillance, replenishments at sea, defensive air combat training, close-in coordinated maneuvers, and other training", said a statement from the Navy's 7th Fleet, which is responsible for monitoring the Pacific including North Korea.
Trump continued his tough talk against Pyongyang on Friday in a speech to business leaders at the Asia-Pacific Economic Cooperation summit in Danang, Vietnam, saying that the region's future "must not be held hostage to a dictator's twisted fantasies of violent conquest and nuclear blackmail", referring to North Korean leader Kim Jong Un.
Self-driving shuttle crashes on maiden voyage
Before you think this proves that self-driving cars have no place in this world, the shuttle wasn't at fault for the accident. This material may not be published, broadcast, rewritten, or redistributed. "It's going to hit us.' And then it hit us".
The leaders also agreed to continue their discussions next month when the South Korean president will make a trip to China for their third bilateral summit, according to Cheong Wa Dae.
In recent months, North Korea has tested intercontinental ballistic missiles that could reach the USA mainland with further development and has conducted its most powerful nuclear test.
The writers argue that China never intended the informal sanctions it slapped on South Korea after the deployment of a US Terminal High Altitude Area Defense (THAAD) antimissile system to be long term.
Now, a meeting between Chinese president Xi Jinping and his South Korean counterpart Moon Jae-in appears to have strengthened relations between the countries.
Trump has embarked on a tour of Asia this week trying to rally regional support for curbing North Korea's nuclear weapons programme, warning that time is running out over the crisis.
Though China has backed United Nations sanctions, USA officials want Chinese authorities to clamp down on unauthorised trade along the North Korean border.