U.S. President Barack Obama told his Chinese counterpart Xi Jinping on Saturday he wanted candid talks on thorny bilateral issues such as cyber security, human rights and maritime concerns.
The leaders of the world's two biggest economies were meeting on the sidelines of the G20 summit in the eastern Chinese city of Hangzhou.
China is keen to ensure a smooth G20 summit, its highest profile event of the year, as it looks to cement its global standing and avoid acrimony over a long list of tensions with Washington.
Obama, attending his last gathering of the world's 20 major economies before stepping down in January, wants to stress the urgency of curbing global climate change and to urge other leaders to use fiscal policy to boost economic growth.
The trip also potentially marks Obama's final meeting as president with Xi. During his eight-year presidency, the two countries have grappled with hacking incidents and differences over territorial disputes in the South China Sea.
"I know that we will have once again candid conversations about some of those differences: issues like human rights or cyber or maritime," Obama told Xi at the start of their meeting.
The visit got off to a rocky start when a Chinese government official angrily scuffled with Obama's top national security adviser, Susan Rice, at the airport, and yelled at a press aide.
In recent months, China has been incensed by a ruling against its claims in the South China Sea by an international court, a case initiated by Manila but blamed by Beijing on Washington.
Cyber issues, from concern over hacking and cyber espionage to emerging Chinese policies on information technology that foreign companies fear could limit their operations in the country, have also strained ties.
"I look forward to an extensive discussion on our shared interests in advancing regional and global security, from the Korean peninsula to the fight against ISIL," Obama said, using an acronym for the Islamic State militant group.
Obama said the United States welcomed China's contributions to global development, peacekeeping and refugee assistance.
"We're also setting the stage so that the next U.S. administration comes in with a relationship that is on a strong and productive footing," he said.
Xi told Obama it was the responsibility of China and the United States to carry out a successful G20 summit and to "inject momentum to the global economy while lifting confidence," according to the official Xinhua news agency.
"Important progress was also made in fighting cyber crimes, coping with the Ebola epidemic in Africa, and facilitating a comprehensive agreement on the Iranian nuclear issue," Xinhua cited Xi as saying on U.S.-China cooperation.
Earlier in the day, the United States and China - the world's two biggest emitters of greenhouse gases - both formally ratified the Paris agreement to curb climate-warming emissions, which could help put the pact into force before the end of the year.
