The casual setting at Sunnylands, California, will give Chinese President Xi Jinping and US President Barack Obama a lot of unscripted time in the coming two days, but their topics will be prickly, with cyber security high on the agenda.

At a White House conference call, senior administration officials indicated the US would be taking a hard line with China over the issue.

"Governments are responsible for cyber attacks that take place from within their borders… We will raise with China any concerns we have about intrusions we believe emanate from China," they said. "We expect it to become a standing issue in the US-China relationship given the importance of cyber strategy in the global economy."

Qin An, director of the China Institute of Cyberspace Strategy, told the Global Times that the two countries face common threats in this field. "Instead of overshadowing the meeting, a frank discussion between Xi and Obama would be conducive to finding a solution and set a tone for the future."

The two countries will hold their first working-level discussion on cyber security under the framework of a strategic security dialogue in July.

While expressing concerns over the issue, White House officials also told reporters they would not let the meeting become a "cyber summit," adding that North Korea, Syria, human rights and many other pressing issues are also likely to be discussed.

The summit will give the two presidents a chance to "begin from a high starting point," officials said at the briefing. The meeting is scheduled to start around 4 pm Friday, followed by a private dinner Friday evening and private discussions Saturday morning.

The informal get-together suggests not only Xi's greater confidence, but also his recognition that the bilateral relationship is "at a critical juncture," Bonnie Glaser, chair in China studies at the Center for Strategic and International Studies, a Washington DC-based think tank, told the Global Times.

Glaser described the meeting as "unprecedented," noting the potential for managing tough issues will be increased if the two leaders can build a personal rapport.

White House press secretary Jay Carney Monday said the meeting would not try to end with "so-called deliverables."

Qu Xing, director of the China Institute of International Studies, told the Global Times that involved topics would be "too complex to draw conclusions," but the two leaders could exchange their opinions through in-depth discussions on a broad array of issues.

"It is flexible and could allow Xi and Obama to raise tentative ideas, which wouldn't be viewed as formal stances held by the governments," Qu said.