"I want to warn North Korea to do no more risky gambling", added Moon.
"If the regime of South Korea truly wants peace, it should not recklessly fault North Korea but clearly understand what is going on now".
The mainly computer-simulated drills and other joint exercises always infuriate Pyongyang, which considers them rehearsals for an invasion despite us insistence that they're defensive in nature.
The statement came after a heated exchange of threats with Washington earlier last week.
"If North Korea completes development of intercontinental ballistic missiles and weaponizes it with nuclear warheads, I will consider that a red line", Moon said.
Ulchi Freedom Guardian, one of two major military exercises carried out by the US and South Korea, involves tens of thousands of troops from both nations drilling to achieve peak readiness in the case of conflict.
His comments followed Mattis' threat that it would be "game on" if North Korea carried out with its threat to fire missiles towards the USA island territory of Guam.
Also in his speech, Moon said that South Korea should play a leading role in the nuclear issue in the peninsula. The U.S. and other countries have accused North Korea of using export income to fund its banned weapons programs.
Huge tree falls down in Central Park, injures woman, 3 children
Antonio Russo of Williamsburg was riding his bike and was about 100 yards away when the tree fell near West 62nd Street. Winds blew between 0 and 3 miles per hour from 9:51 a.m.to 10:51 a.m., according to the National Weather Service.
Dunford was responding to questions about comments by Trump's chief strategist Steve Bannon, who was quoted in an interview with The American Prospect as saying "there's no military solution" to the North Korean problem.
But as State Department spokesperson Heather Nauert said on Tuesday, the U.S. has no plans of stepping them down.
Trump's administration has consistently said military action is on the table and the president has even suggested he's willing to take unilateral action against Pyongyang if it continues to threaten the United States. If North Korea engages in another provocation in the form of a nuclear or missile test, it could lead to controversy over whether such behavior crossed the red line drawn by President Moon.
"Kim Jong Un of North Korea made a very wise and well reasoned decision".
Mr Trump's recent aggressive comments about deploying possible military options underscored his resolve to counter the threat from the North's nuclear weapons and missile programmes.
Both defense leaders reiterated the importance of the alliance and expressed their commitment to build a stronger partnership based on mutual trust and cooperation, White said, noting that they will meet later this month in Washington.
However, the US' top military official, General Joseph Dunford, chairman of the Joint Chiefs of Staff, said in Beijing: "Any military action taken on the Korean peninsula would be in consultation with our allies".