It's been years since China embarked on a major effort to modernize its military, all the while becoming increasingly assertive in pressing its claim in places like the South China Sea. Now, a report from the U.S. Defense Department says Beijing is actively looking to project its power farther than ever before.
China's military muscle has been most visible on the high seas - where it has dispatched ships to press its claims to uninhabited islands also claimed by Japan.
There was also the recent deployment of new ballistic missiles along China's southern coast.
David Helvey is U.S. Deputy Assistant Secretary of Defense.
"We're concerned about the ability of China to develop missiles that can project its military power with precision great distances from China," said Helvey.
But it's not just missiles. China is investing in submarines, new fighter jets, and it even launched its first aircraft carrier.
"The issue here is not one particular weapons system," he said. "It's the integration and overlapping nature of these weapons systems into a regime that can potentially impede or restrict free military operations in the western Pacific."
In March, China announced it was increasing its defense budget by almost 11 percent, to $114 billion this year. And U.S. defense officials say unreported spending could be pushing China's total military spending upwards of $200 billion.
Another cause for U.S. concern is Beijing's focus on space programs and a growing number of attacks in cyberspace, including on U.S. government systems, that the Pentagon says "appear to be directly attributable" to China's government.
The cyber-security firm Mandiant says it has traced scores of those attacks to hackers operating near this Shanghai military building.
The Pentagon report says it is all part of a long-term strategy designed to expand China's reach far beyond its own borders.