Following his June meeting with Kim Trump promised to end the war games with South Korea.
But there was also a loaded message for Mr Kim, mixing an expression of goodwill to the North Korean autocrat with an implicit military threat that will add to speculation over the direction of Mr Trump's attempted rapprochement with a long-time adversary. The letter said North Korea felt talks had stalled because "the U.S. is still not ready to meet [North Korean] expectations in terms of taking a step forward to sign a peace treaty". "South Korea war games", it added.
Long Guoqiang, deputy director of the Development Research Center of the State Council, wrote: "The trade war is not just a measure for the U.S. to gain more economic benefits, it is also an important strategy to contain China".
"The US is trying to pressure North Korea into making progress in denuclearization talks, but certain developments in inter-Korean relations that are not in tandem with the progress in talks could distract their goal", said Kim Joon-hyung, an worldwide studies professor at Handong Global University. "South Korea agreement concerning the postponement of joint drills, and there has been no other agreement", South Korea's foreign ministry said in a statement on Wednesday.
The move was broadly criticised as a premature concession to North Korea, which has resisted USA efforts to persuade it to give up its nuclear weapons.
In the past week, the United States has hit China with $16 billion in tariffs on Chinese imports.
Following that announcement, more sanctions were imposed by the United Nations in December. On Wednesday the president accused Beijing of pressuring the North because of current tensions in U.S.
There is "no reason at this time" to spend large amounts of money on the joint U.S. "Their relationship and bond remain very strong".
Hua said that China has reiterated its position on the issue.
The cancelation of the trip was reportedly prompted by a belligerent letter to Pompeo from North Korea's ruling Workers' Party Central Committee Vice Chairman Kim Yong Chol. "We will work very closely, as I said, with the secretary of state, what he needs done, we will certainly do to reinforce his effort, but at this time there is no discussion about further suspensions".
North Korean leaders could be lashing out after President Trump stopped plans for Pompeo to make what would have been his fourth visit to North Korea, citing insufficient progress on the issue of denuclearization.
"(The South's) supply of all materials, equipment, and energy is for the convenience of our officials and operation of the office, so we believe (the office) does not undermine the goal of the sanctions as it does not offer economic benefit to North Korea", Foreign Ministry spokesman Noh Kyu-duk said during a regular briefing.
The paper also claimed that the USS Michigan, a nuclear Navy submarine, transported Green Berets and other special forces from Okinawa, Japan, to the Jinhae naval base in South Korea in late July or early August. If he does, they will be far bigger than ever before.
In June, after the Singapore Summit, the United States said it would suspend "select" exercises with South Korea, including the large-scale Ulchi Freedom Guardian exercises slated for August.
"We're making no change to the exercise program at this time", Mattis said on Tuesday.