President Barack Obama pushed Chinese President Xi Jinping to do more to address the online theft of U.S. intellectual and other property coming from his country and said the hacking is "inconsistent with the kind of relationship we want to have with China," a top White House aide said.

Obama national security adviser Tom Donilon said discussion of cybersecurity took up much of the Saturday morning meeting between the two leaders, which ended with few policy breakthroughs but the prospect of stronger personal ties.

Donilon said Obama described in detail instances of hacking against U.S. companies by entities in China and said the U.S. didn't have any doubt who was behind them.

"The president underscored that resolving this issue was really key to future economic U.S.-China relations," Donilon told reporters after about eight hours of meetings Friday and Saturday. The gathering at the sprawling Sunnylands estate in the California desert was their first meeting since Xi took office in March.

Obama "asked that the Chinese government engage on this issue and understand that if it's not addressed, if it continues to be this direct theft of United States property, that this was going to be a very difficult problem in the economic relationship and was going to be an inhibitor to the relationship really reaching its full potential."

Xi's senior foreign policy adviser, Yang Jiechi, told reporters that cybersecurity shouldn't be the cause of friction but an area of cooperation for two nations that face similar challenges. 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."

Yang said the two leaders "blazed a new trail" away from the two nations' past differences in the summit and "talked about cooperation and did not shy away from differences."

"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," Yang said.

"We have to stay each other's partners, not rivals," Yang said.

Donilon also said the leaders found "quite a bit of alignment" on the subject of North Korea and "agreed that North Korea has to be denuclearized and that neither country will accept North Korea as a nuclear-armed state."

The leaders left the final remarks on the summit to their aides and closed the summit in low-key style, with no formal statements to the press, just a private tea with Xi's wife.

The White House said in a statement shortly after 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.

U.S. officials are hoping that Xi proves to be a new brand of Chinese leader. He has deeper ties to the U.S. than his predecessors, given that he lived in Iowa briefly as a visiting official and sent his daughter to college in the U.S.

The two leaders appear to have more in common than Obama had with former Chinese leader Hu Jintao, who often appeared stiff and formal in meetings. Both men are in their 50s and share a love of sports: swimming and football (soccer) on Xi's side, basketball and golf on Obama's. Both are also married to glamorous, high-profile wives who have played a strong role in shaping their images.

During their talks, the two men also spent time explaining to each other how their life experiences have shaped their world views, an Obama administration official said.

Xi talked about growing up in the Chinese countryside during his country's cultural revolution and the perspective it gave him on his country's development. And Obama explained about how his childhood in Hawaii shaped his view of the U.S. as a Pacific power.

The Chinese leader broke out a bottle of "Maotai," a famous Chinese liquor, to toast Obama during Friday's working dinner, according to the official, who insisted on anonymity in order to discuss the private meetings.

The two leaders will likely meet again in September, on the sidelines of an international economic summit in Russia. Xi also invited Obama to travel to China soon for a similarly informal round of one-on-one talks.

Ahead of the weekend summit, the U.S. emphasized that Obama would press China on its alleged cyberhacking against the American government and businesses. But Obama and Xi carefully avoided publicly accusing each other's nation of high-tech intrusions, though they acknowledged an urgent need to find a common approach on addressing the matter.

Obama said the United States and China were in "uncharted waters" regarding computer security.

"We don't have the kind of protocols that have governed military issues and arms issues, where nations have a lot of experience in trying to negotiate what's acceptable and what's not," Obama said during a Friday night news conference with Xi.

Obama also sought to distinguish between China's alleged cyberspying and his own government's monitoring of U.S. phone and Internet records. He insisted the two issues were separate and distinct, and that concerns over hacking and intellectual property theft shouldn't be confused with the debate over how governments collect data to combat terrorist threats.

"That's a conversation that I welcome," he said.

Xi, who called rapid technological advancements a "double-edged sword," claimed no responsibility for China's alleged cyberespionage. He said China was also a victim of cyberspying but did not assign any blame.

Xi has been expected to press China's claims of business discrimination in U.S. markets and to express concern over Obama's efforts to expand U.S. influence in the Asia-Pacific region. China sees that as an attempt to contain its growing power.

On North Korea, U.S. officials said Obama was looking to build on Xi's apparent impatience with North Korea's nuclear provocations. The U.S. has welcomed Xi's recent calls for North Korea to return to nuclear talks, though it's unclear whether the North is ready to change its behavior.

Xi departed California Saturday afternoon. Obama planned to stay in California through the weekend, though he had no public events planned.

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Associated Press writer Darlene Superville contributed to this report.

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