United States Defence Secretary Chuck Hagel has accused China of being involved in cyber attacks, delivering one of the most public warnings yet to Beijing about the online intrusions.
"The United States has expressed our concerns about the growing threat of cyber intrusions, some of which appear to be tied to the Chinese government and military,'' he said at the the Shangri-La Dialogue on Saturday.
In his speech to top defence officials from the region, Europe and the US, Mr Hagel urged Beijing to work more closely with Washington to step up responsible behaviour in cyberspace and promote peace and stability in Asia.
He called for both countries, which have "many areas of common interest and concern", to set up a working group to foster dialogue on cyber security.
"We are determined to work more vigorously with China and other partners to establish international norms of responsible behavior in cyberspace," Mr Hagel told some 350 delegates, comprising defence ministers, the military brass, and security experts, at the annual security summit which is organised by the London-based International Institute of Strategic Studies.
Mr Hagel also said that the US welcomes a "strong, emerging and responsible China" which it work together with to solve regional and global problems that include North Korea's effort to develop nuclear weapons and missiles, and competing territorial claims in the South China Sea.
Although both countries have differences, they can be addressed through continuous and respectful dialogue, added Mr Hagel.
"It also requires building trust and reducing the risk of miscalculation, particularly between our militaries."
In his 35-min speech, Mr Hagel also assured that America's efforts to "rebalance'' to Asia, a strategy which was first laid out by his predecessor Leon Panetta at last year's Shangri-La Dialogue, was "on track".
He told Asian nations that despite sharp budget cuts, the Pentagon will continue to shift its military troops, ships and aircraft to the Pacific region.
The build-up means that the US Air Force would commit 60 per cent of its overseas-based aircraft and airmen to the region - about the same as the current level - while US Army troops and Marines would resume their Asia-Pacific roles as they draw down following the wars in Iraq and Afghanistan.
Future deployments to this part of the world would include the most advanced weapons systems like radar-evading F-22 Raptor jet fighter, the stealth F-35 Joint Strike Fighter and the Virginia-class fast attack submarine.
"It would be unwise and short-sighted to conclude ... that our commitment to the rebalance cannot be sustained," said Mr Hagel.