"A dialogue between South and North Korea must resume". Steve Bannon, the White House's chief strategist, told The American Prospect that there was no military solution to Pyongyang's nuclear threat. "The alternative would have been both catastrophic and unacceptable!" The initiative has been supported by Russian Federation but rejected by the United States.
"Since yesterday we are a bit more optimistic", Gabriel said.
Moon said "President Trump is trying to pressure North Korea by showing firm determination".
The 10-day command post exercise known as Ulchi Freedom Guardian is to begin Monday and will involve tens of thousands of us and South Korean servicemembers.
Mr Trump tweeted on Wednesday that Kim Jong Un had: "made a very wise and well-reasoned decision", amid indications that he does not immediately plan to fire multiple missiles toward Guam.
Mr Moon wants to engage with the North, but his efforts have so far been met with a string of threats and missile tests as Pyongyang works to build nuclear-armed missiles that can reach the USA mainland. When asked about potential unilateral U.S. action, he said, "that's purely speculative and a decision to do that would be by the president".
He also commented that "the United States sought to put maximum pressure and sanctions through the latest UN Security Council resolution", while at the same time it is "seeking unilateral measures".
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".
Moon also insisted that "any military action to be taken on the Korean Peninsula requires South Korea's consent unless it is taken outside the peninsula".
Moon said he believes the two Koreas must restart a dialogue, but it will take time.
The South Korean leader also said North Korea's development of nuclear weapons technology was "nearing" a red line, which he described as "completing an ICBM and weaponizing it with a nuclear head". He urged the North to halt its efforts to develop a nuclear-tipped weapon that could reach the USA mainland.
Moon said Washington and Seoul are closely communicating over the North Korean nuclear problem and share the view that strong sanctions and pressure are needed against Pyongyang to stop its provocations and force it into negotiations to give up its nukes. It also conducted two underground nuclear tests in 2016.
South Korean President Moon Jae-in proposed a trilateral discussion with the USA during a summit with Chinese President Xi Jinping last month in a bid to ease Beijing's resistance to the deployment of a United States missile shield here, Seoul officials said Wednesday.