North Korea, which has developed an intercontinental ballistic missile some expert observers assess is capable of delivering a nuclear payload to cities across America, is livid and threatening to retaliate.
The preparations come amid a tense escalation of threats between the USA and North Korea over the latter's recent gains in nuclear weapons technology and its successful launch of an intercontinental ballistic missile that theoretically could hit cities on the east coast of the United States.
The question of whether Beijing would go along with much harsher sanctions against North Korea was answered this weekend.
United States policy towards North Korea under the last three Presidents has been to place the problem firmly in the hands of the Chinese.
Speaking at a regional security forum in Manila this week, Mr Wang said the new resolution showed China and the global community's opposition to North Korea's continued missile tests, the foreign ministry said in a statement on Tuesday.
China, North Korea's lone major ally, has repeatedly said it is committed to enforcing increasingly tough United Nations resolutions on North Korea, though it has also said what it terms "normal" trade and ordinary North Koreans should not be affected.
"It is conceivable that North Korea's nuclear weapons program has already considerably advanced and it is possible that North Korea has already achieved the miniaturization of nuclear weapons and has acquired nuclear warheads", it said.
"It would be a very costly war, in terms of... in terms of the suffering of mainly the South Korean people", he said. "If it believes it is only North Korea rather than the US and South Korea as well to blame for the nuclear issue, this ill-fitting mindset will not help solve the crisis", it said.
"The North Koreans contend that they can not relinquish their nuclear program until the USA ends its hostile policies", she said.
Recent satellite photos suggest North Korea could be preparing for fresh submarine-based ballistic missile tests, an expert on its military has said.
"We will know it when we see it", he told reporters.
"We support the positive proposals put forward by the new (South Korean) government".
The latest United Nations resolution bans North Korean exports of coal, iron, iron ore, lead, lead ore and seafood.
In a phone call, South Korea's Moon and Trump said they would continue cooperating to rein in North Korea, particularly ahead of a regular joint military drill set for late August, South Korean presidential office spokesman Park Su-hyun said.
On the sidelines, the foreign minister met his counterparts including China, Russia, Indonesia, East Timor and the host country Philippines.
The White House said the two leaders "affirmed that North Korea poses a grave and growing direct threat" to most countries around the world.