Chinese president Xi Jinping has warned Donald Trump that "some negative factors" are hurting US-Chinese relations, as tensions flared between the two nations.
Mr Xi's comments during a phone call with the US president follow Beijing's displeasure over American arms sales to rival Taiwan, US sanctions against a Chinese bank over its dealings with North Korea and, most recently, the sailing of a US destroyer within the territorial seas limit of an island China claims.
Beijing was also irritated after the US state department gave Beijing a dismal grade last week in a new human trafficking report.
As reported by state media, Mr Xi told Mr Trump that Beijing expects Washington to continue managing relations on the basis of the "one China" principle that rules out formal contacts with Taiwan, which China claims as its own territory.
"Xi Jinping emphasized that, since my meeting with the president at Mar-a-Lago, China-US relations have achieved important outcomes," state broadcaster CCTV reported, referring to Mr Xi's meeting with the American leader in Florida in April.
"At the same time, bilateral relations have been affected by some negative factors. China has expressed its position to the US."
Seeking to lighten the message, Mr Xi also said that China-US relations had achieved "important outcomes" since the Florida meeting.
It is unclear whether any of those issues will come up in discussions at the G20 summit in Germany this week at which Mr Trump and Mr Xi are expected to hold a bilateral meeting.
It now appears that China is pushing back against the US pressure, setting the stage for a potential confrontation.
China's foreign ministry accused the US of violating Chinese sovereignty and disrupting "peace, security and order of the relevant waters" after the US Navy destroyer USS Stethem sailed within 12 nautical miles of the tiny Triton island in the South China Sea, which is claimed by China, Taiwan and Vietnam.
China's defence ministry issued a similar statement, saying it would bolster patrols and take precautions commensurate with the threat level to safeguard "national sovereignty and security".
Mr Trump and his top advisers have done little to hide their irritation over what they see as the reluctance by China, North Korea's main economic partner, to tighten the screws on Pyongyang over its nuclear and missile programmes.
Until lately, US officials had been describing China as a partner in their strategy to prevent North Korea from developing the ability to strike the US mainland with nuclear weapons.
However, last month Mr Trump hinted at a loss of patience, tweeting that his bid to secure a tougher Chinese approach "has not worked out".
Asked about the state of ties, Chinese foreign ministry spokesman Geng Shuang said it was normal to encounter "some issues in the process of developing the bilateral relationship".
He added: "We believe that the significance of our bilateral relationship has already exceeded the bilateral scope and is exerting important influence on the development of the whole world.
"On our part, we are willing to develop the bilateral relationship based on non-confrontation, mutual benefit and mutual trust, expand cooperation and properly manage differences between the two countries so as to further advance the bilateral relationship."