US President Donald Trump has hailed his personal relationship North Korean leader Kim Jong Un and says there is no reason to resume war games with South Korea.
Wednesday's statement from the White House comes a day after the US defence secretary hinted that the drills could resume.
The White House, in a statement sent on Twitter by Trump, said the US president believed North Korea was under "tremendous pressure" from China, but that Beijing was also supplying Pyongyang with "considerable aid," including fuel, fertiliser and commodities.
"This is not helpful!" the statement said.
"Nonetheless, the president believes that his relationship with Kim Jong-un is a very good and warm one, and there is no reason at this time to be spending large amounts of money on joint US-South Korea war games," it added.
"Besides, the president can instantly start the joint exercises again with South Korea, and Japan, if he so chooses.
If he does, they will be far bigger than ever before."
The statement also said the US trade dispute with China and other differences "will be resolved in time by President Trump and China's great President Xi Jinping.
Their relationship and bond remain very strong."
Chinese Foreign Ministry spokeswoman Hua Chunying said the remarks regarding China's role on the North Korea issue were "irresponsible".
"The US side's irresponsible distortion of facts and logic is world-leading and really not something the ordinary person can understand," Hua told a regular news briefing on Thursday in Beijing when asked about Trump's tweet.
The statement came after US Defence Secretary Jim Mattis said, amid a breakdown in diplomacy with North Korea over its nuclear weapons program, that the US military had no plans yet to suspend any more major military exercises with South Korea.
Mattis said no decisions had been made about major exercises for next year, but noted that the suspension of drills this summer as a good-faith gesture was not open-ended.
Trump caught many American military planners off guard when he announced after his June 12 summit with Kim Jong-un that the United States was suspending this summer's drills with South Korea.
The move was broadly criticised as a premature concession to North Korea, which has appeared to resist US moves to persuade it to give up its nuclear weapons.
At the June summit Kim agreed in broad terms to work toward denuclearisation of the Korean peninsula.
But North Korea has given no indication it is willing to give up its weapons unilaterally as the Trump administration has demanded.
Trump last week called off a visit to North Korea by Secretary of State Mike Pompeo just hours after Pompeo announced it and publicly acknowledged for the first time that his efforts to get Pyongyang to denuclearise had stalled.