US President Barack Obama congratulated his new Chinese counterpart, Xi Jinping, on Thursday, telling the newly confirmed leader in a phone call that he hoped their countries would continue to expand cooperation including in the sensitive area of cybersecurity.

The White House described the nature of the call but didn't indicate what kind of response Obama received from Xi, who just hours earlier had been chosen as president by the National People's Congress.

Xinhua News Agency reported that Xi, during his conversation with Obama, expressed "China's principles and positions" regarding the Korean Peninsula, cybersecurity and other issues.

Currently, US-China relations are faced with a historic opportunity to chart a course for future development, said Obama, according to Xinhua.

Xi said the two countries should jointly maintain and promote the sound development of a series of mechanisms, including the Strategic and Economic Dialogue and high-level consultations on humanistic exchanges.

That Obama was quoted by the White House as stressing greater focus on cybersecurity - he called it a "shared challenge" - suggests the divisive issue might give way to some form of cooperation. Obama is said to have tied cybersecurity to trade, investment and intellectual-property protection - key topics between the world's two biggest economic powers.

Earlier this week, Obama's national security adviser, Thomas Donilon, said the United States is working to strengthen ties to emerging powers, including a "stable, productive and constructive relationship" with China. He called cybersecurity "a growing challenge" that the two countries should address.

Donilon's remarks prompted a Chinese foreign ministry spokeswoman, Hua Chunying, to say that China hopes to enhance cooperation with the US. She added that Beijing, "on the basis of the principles of mutual respect and trust", would cooperate with the international community, including the US, on cybersecurity. Hua described it as a "global issue" that requires "rules and cooperation, instead of a cyberspace war".

Obama also told Xi of the US commitment to "increasing practical cooperation to address Asia's and the world's most pressing economic and security challenges". On the nuclear and ballistic-missile threats from the Democratic People's Republic of Korea, the US president also stressed the need for coordination with China to ensure that Pyongyang meets its denuclearization pledges.

Also on Thursday, the US Treasury Department announced that Treasury Secretary Jack Lew will visit Beijing next week to meet China's new leaders. Lew will visit the Chinese capital on Tuesday and Wednesday, his first official trip abroad since being confirmed as secretary by the US Senate on Feb 27.

The two-day trip will include meetings with the newly elected Xi and senior economic officials to discuss bilateral relations and explore opportunities for cooperation and growth, the Treasury Department said. Lew will "discuss efforts to level the playing field and create new opportunities for US workers and businesses", according to Thursday's announcement.

Experts said Lew's visit, announced soon after the NPC confirmed Xi in Beijing, is a way to show that the US recognizes the importance of its interdependent relationship with the world's No 2 economy.

"This trip is certainly a way to court the new Chinese leadership - the timing is an acknowledgement and perhaps an offer of support," said Ann Lee, an economics professor at New York University and author of What the US Can Learn from China.

"The fact that this is Lew's first overseas trip, and that he will be the first major foreign visitor the new leadership in Beijing will receive, undoubtedly underscores the importance both sides attach to this growing relationship," said Zhu Zhiqun, a political-science professor at Bucknell University in Pennsylvania.

Lew, 57, previously served as Obama's chief of staff and before that was White House budget director under the current president and Bill Clinton. He is seen more as a specialist on domestic economic policy than as a globetrotting finance expert. Compared to his predecessor at Treasury, Timothy Geithner, who speaks Mandarin, Lew has limited international experience, including with China.

Lew, a chief operating officer of two Citigroup Inc units between 2006 and 2009, was pressed by senators in his confirmation hearings to make US claims that China has been slow in letting its yuan currency float freely a top priority as Treasury chief. Many US officials blame the yuan's weakness against the dollar a major reason for the US trade deficit with China, which soared to $315 billion in 2012.

China, the United States' largest creditor, held $1.2 trillion in US Treasury issues as of December, according to the Treasury Department.

Lee, the NYU professor, said the secretary would be wise to avoid raising politically sensitive issues during this initial visit.

"Lew should tell China what China wants to hear," she said. "If he pushes the American agenda, China may resist. It would be wise if he doesn't pressure China on the currency issue since China plans to reform its currency policy anyway."

Douglas Paal, director of the Asia program at the Carnegie Endowment for International Peace in Washington, called the timing of Lew's trip "puzzling" though he said it may be a gesture to show China that the US remains "engaged".

"Issues supervised by Treasury are not now at the forefront of US-China relations, far from it," Paal said. "Obviously, the US has an interest in understanding whether the new Chinese administration is going to speed up the implementation of rebalancing the Chinese economy."

The White House also confirmed on Thursday that US Secretary of State John Kerry will visit China in April as part of an Asia trip on which he'll also stop in Japan and the Republic of Korea.

"Secretary Kerry's undated future visit suggests that the White House recognizes that economics are not the only issue when the Korean peninsula, East China Sea and other areas such as cyberspace are growing hotter," Paal said.

yuweizhang@chinadailyusa.com