Cho added that South Korea and the USA agreed during a visit to Seoul by Trump's national security advisers on Monday to formulate a "bold and pragmatic" joint approach.
A senior foreign policy adviser to Chinese President Xi Jinping stressed the importance of relations with South Korea on Friday as the two countries attempt to mend a rift in ties over the deployment of a USA missile-defense system to guard against North Korean threats.
Harris also cautioned that the missile launch indicated a major advancement in the North's technological capabilities and called for further coordination among Japan, South Korea and the USA to deal with the increasing North Korean threat.
After the missile launch on Sunday, the United States, Japan and South Korea called a UN Security Council meeting to press the DPRK to change course and dismantle its missile and nuclear programmes.
"The reality is that there is a high possibility of a military conflict at the NLL (Northern Limit Line) and military demarcation line", Moon said.
Unlike his two conservative predecessors, Moon, a liberal, has emphasized the importance of dialogue in dealing with North Korea, saying that his predecessors' hard line, which focused on sanctions, had failed to prevent the North from expanding its nuclear weapons and missiles arsenal.
"North Korea seems to be very aware of the US attack on Syria, it quoted Jiro Ishimaru, editor for North Korean magazine Rimjingang as saying, according to South Korea's Yonhap News Agency".
North Korea conducted two nuclear tests a year ago, which are likely to have improved its know-how in making nuclear weapons small enough to fit on long-range missiles.
Moon's remarks came in a telephone conversation with United Nations.
The remarks, made in a meeting with South Korea's special presidential envoy Hong Seok-hyun, is the latest in a series of signs that the USA may be moving toward dialogue and engagement with Pyongyang after months of exchanging saber-rattling and harsh rhetoric.
"But there are no specific steps in the offing", Lee Duk-haeng, a spokesman for South Horea's unification ministry, told reporters.
The message to the Seoul came less than 10 hours later after the DPRK publicly criticized the Moon government's response to its test-firing of the Hwasong-12 ballistic missile on Sunday.
The two Koreas - technically still at war after the 1950-53 conflict ended only with a ceasefire instead of a peace treaty - have occasionally clashed along the border. It has also regularly threatened South Korea and Japan of strikes for colluding with the United States.
Moon's envoy, South Korean media mogul Hong Seok-hyun, said Trump spoke of being willing to use engagement to ensure peace. Hong said South Korea had not yet received official word from Washington on whether Seoul should pay for a USA anti-missile system that has been deployed outside Seoul.
If North Korea cooperates the United States could possibly support reduction in sanctions. Relations between Seoul and Beijing have soured, since the deployment of a US missile defense system known as THAAD, to the Korean peninsula. The US policy is to further isolate North Korea and increase sanctions whereas Moon wants a policy of engagement to attempt to improve relations between the North and South.
"We are determined to take care of South Korea, which is why we have our mission there, working and that, as well", Haley said on "This Week".