U.S. Defense Secretary Chuck Hagel is using an annual security forum in Singapore to publicly accuse China's government of carrying out cyber attacks on U.S. targets.
In a speech at the Shangri-La Security Dialogue on Saturday, Hagel said the U.S. has "expressed concerns about the growing threat of cyber intrusions, some of which appear to be tied to the Chinese government and military."
The Pentagon chief said the U.S. is determined to work with China and other nations to "establish international norms of responsible behavior in cyberspace." He has said he plans to discuss the issue with Chinese delegates on the sidelines of the conference.
Recent U.S. government and media reports say Chinese computer hackers have stolen data from dozens of Pentagon weapons programs and other defense technologies. China denies the allegations, but has not responded to the latest statement by Hagel.
The comments come just days before Chinese President Xi Jinping meets with U.S. President Barack Obama in California, where officials say cyber attacks will also be discussed.
While Hagel on Saturday noted that the U.S. has differences with China, he said Washington looks forward to closer cooperation with Beijing, saying it is important for "these differences to be addressed on the basis of a continuous and respectful dialogue."
Many in China are worried the U.S. is trying to contain Beijing's rising economic power. Of particular concern is Washington's strategic and military rebalance toward the Asia-Pacific.
Addressing the so-called "Asia pivot," Hagel said the U.S. military will devote more air power, ground troops and weaponry to the region as it moves ahead with the strategy.
As part of the pivot, he said the U.S. Air Force will allocate 60 percent of its overseas assets to the Asia-Pacific. The comments expanded on those by his predecessor Leon Panetta, who told the summit last year that the Navy will send 60 percent of its forces to the region by 2020.