A senior Chinese official has said President Barack Obama and Chinese leader Xi Jinping "blazed a new trail" away from the two country's differences in the past at a two-day summit.
Mr Xi's senior foreign policy adviser, Yang Jiechi, said the two leaders "talked about cooperation and did not shy away from differences" in about eight hours of talks on Friday and Saturday.
The gathering at the sprawling Sunnylands estate in Califiornia was their first meeting since Xi took office in March.
Mr Yang said the international community expects relations between the world's two largest economies to steadily improve and grow, and they are committed to working more closely together.
He called it "a strategic, constructive and historic meeting."
"The two presidents agreed to build a new model of major country relationship between China and the United States based on mutual respect and win-win cooperation," Mr Yang said. "We have to stay each other's partners, not rivals.".
Mr Obama told reporters that the talks were "terrific" as he and Mr Xi opened their second day of talks by walking side-by-side through the manicured gardens of the sprawling Sunnylands estate. The unusual summit site was aimed at fostering more candid and free-flowing discussions on numerous high-stakes issues, including cybersecurity, North Korea's nuclear provocations and the economy.
Mr Yang said cybersecurity should not be the cause of friction but an area of cooperation for two nations that face similar challenges. Mr Yang said China "is against all forms of hacking and cyberattacks. China itself is also a victim of cyberattacks and we are a staunch supporter of cybersecurity."
The leaders closed the summit in low-key style, with no formal statements to the press, just a private tea with Mr Xi's wife.
The White House said in a statement shortly after Mr Xi departed the sprawling estate that the two nations agreed to work together for the first time to reduce hydrofluorocarbons, a potent greenhouse gas. The agreement was cast as a significant step toward tackling climate change.