Trump said unless China exerts its pressure on North Korea, the USA will have to take unilateral action.
The South Korean government separately proposed reopening Red Cross talks to discuss ways to resume family reunions.
The ministry of south Korean Defense proposed an interview Friday at Panmunjom, the "village of the truce", at the border between the two Koreas. The previous president Park Geun-Hye had refused to include language as long as Pyongyang did not take any concrete action towards the denuclearization.
"North Korea must respond to our proposals honest if it is truly peace on the Korean peninsula", told reporters Cho Myoung-Gyon, south Korean minister of Unification.
"We anticipate the North's side making a positive response" to the proposal, Suh said.
Maruyama said the Japanese government is "aware of the announcement", but made clear that immediate talks aren't the approach it supports.
Outside experts believe the South Korean broadcasts and leaflets sting in Pyongyang more because the authoritarian country worries that the broadcasts will demoralize front-line troops and residents and eventually weaken the grip of absolute leader Kim Jong Un.More news: New Star Wars teaser shows off Ireland's Skellig Michael
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Scrutiny of China's commercial ties with its isolated neighbor intensified further following North Korea's first test of an intercontinental ballistic missile two weeks ago. When asked whether Seoul consulted with Washington, Cho replied that the countries "mutually cooperated" on the matter. Seoul began blaring anti-Pyongyang broadcasts and K-Pop songs via border loudspeakers, and Pyongyang responded with its own border broadcasts and launches of balloons carrying anti-South leaflets.
The group proposed the family reunion to be held on October 4, in time for the Chuseok holiday, Korea's harvest festival.
Without directly mentioning the proposals, North Korea said through its state-run newspaper Rodong Sinmun on Monday that Moon's Berlin speech was "fortunate" in that it pledged to respect and implement the June 15, 2000, inter-Korean joint declaration of peace and prosperity, but that it contained "ill intention".
According to the UNFPA, the North Korean population grew from 22.35 million in 2008 to 24.21 million in 2014.
North Korea once again urged Seoul to ditch its pro-U.S. stance, saying it was the "starting point" of improved relations with the regime.
Moon suggested earlier this month hostile military activities at the border be ended on July 27, the anniversary of the 1953 armistice agreement that ended the Korean War.