Tensions have spiked as President Donald Trump's administration has hinted it will take a tougher line against North Korea, which has conducted two nuclear tests and test-fired almost 30 missiles since a year ago.
He wrote: "I explained to the President of China that a trade deal with the US will be far better for them if they solve the North Korean problem!"
The North may stage a "strategic provocation" to mark key political dates this month, Kim said, adding that Wu's visit would serve as a "strong warning" against Pyongyang.
Meanwhile, China has downplayed reports that Beijing has deployed 150,000 troops to its border with North Korea.
In a show of force last week, Washington rerouted the Carl Vinson nuclear strike group into Korean waters, after having cancelled its planned trip to Australia.
President Donald Trump said in a note on Twitter on Tuesday that he told China's President Xi Jinping that Beijing would get a better trade deal with Washington if it helped solve the US problem with North Korea.
A Foreign Ministry spokesman was quoted as saying: "We will hold the United States wholly accountable for the catastrophic consequences to be entailed by its outrageous actions".
However, the ministry's spokesman Moon Sang-gyun said in a briefing Tuesday that any military actions will be "conducted under the robust South Korea-U.S. combined defense posture".
A USA national security review of options on North Korea include economic and military measures.
While the carrier group has been deployed to the Korean Peninsula in the past, lawmakers are wondering how the USA warships will be directed to respond to another North Korean missile test.
"North Korea is looking for trouble", Trump wrote on Twitter. US officials said the carrier was meant to be "a show of presence" in the region, but, nevertheless, North Korea said its presence, and the strike on Syria, were clear signals that the country needed to defend itself against the USA and "boost its defenses".
"We are really anxious about what Washington has in mind for North Korea after it hinted at the possibility of a unilateral military scenario", the ministry said.
White House spokesman Sean Spicer said Trump had put North Korea "clearly on notice" he would not tolerate certain actions, but dismissed Pyongyang's nuclear attack threat.
"This goes to prove that the USA reckless moves for invading the DPRK have reached a serious phase of its scenario", the North's statement said.
China and South Korea agreed on Monday to impose tougher sanctions on North Korea if it carried out nuclear or long-range missile tests, a senior official in Seoul said.
North Korea's leader, Kim Jong Un, recently said the country will soon be capable of testing an intercontinental ballistic missile.
Former MI6 head Sir John Sawers has warned that tensions with North Korea are actually a much bigger threat to world peace than the war in Syria.
Speculation over an imminent nuclear test is brewing as the North marks anniversaries including the 105th birthday of its late founding leader on Saturday - sometimes celebrated with a demonstration of military might. If they do, that will be very good for China, and if they don't, it won't be good for anyone.
South Korea's Ministry of Foreign Affairs likewise emphasized that the United States will not act unilaterally without consulting Seoul on matters involving Pyongyang.