(Reuters) — The United States on Tuesday expressed deep concern about state-sponsored cyber theft and stressed the need to keep Asian sea lanes open at the start of annual talks with China, saying the world depended on the ability of the two countries to narrow their differences.

In opening statements at the wide-ranging Strategic and Economic Dialog forum in Washington, China expressed a desire for constructive relations with the United States, and said the two sides could manage their differences — as long as they accommodated each other's core interests.

U.S. Vice President Joe Biden said China and the United States might not resolve all of their differences during the Cabinet-level meetings that began in Washington on Monday with preliminary talks and a dinner and run into Wednesday, but should commit to working on them.

"We have to keep at it, day after day after day after day," Mr. Biden said. "This relationship is just too important. Not only we depend on it, but the world depends on our mutual success; to put it bluntly, the world is dependent on those of you in this room to continue to work through those issues."

China's Vice Premier Liu Yandong responded to Mr. Biden by saying that differences could be managed "as long as our two countries adopt an overall perspective, respect and accommodate each other's core interests and be committed to a constructive approach to reduce misunderstanding and miscalculation."

The Washington meetings come at a time of waning trust and widening differences between the United States and China, even though they maintain robust economic ties that last year were worth $590 billion in two-way trade.

The United States is particularly worried by massive attacks on government computers that U.S. officials have blamed on Chinese hackers and China's pursuit of territorial claims in the South China Sea, as well as Beijing's challenge to its dominance of global finance and restrictions on U.S. businesses in China.

In the opening session, U.S. Treasury Secretary Jack Lew addressed the former issue without mentioning China by name but said Washington remained "deeply concerned about government-sponsored cyber theft from companies and commercial sectors."

Mr. Lew also said it was critical for China to move toward a more market-oriented exchange rate, repeating a U.S. mantra even though the International Monetary Fund has said the yuan is no longer undervalued.

More than 400 Chinese officials are in Washington for the talks, which involve eight U.S. Cabinet secretaries.

They come at a time when U.S. President Barack Obama is struggling to secure backing from Congress for legislation needed to speed a 12-nation trade deal, which is the economic plank of his "pivot to Asia" policy intended as a counterweight to China's growing influence.

The two sides will try to ease tensions by stressing areas of cooperation, including climate change, shared concerns about Iran and North Korea's nuclear programs, the fight against Islamist militancy, and support for global development.

Despite considerable tension over some issues, China is hoping for a smooth set of meetings to prepare for a visit to Washington by President Xi Jinping in September.