Defense Ministry spokesman Geng Yansheng said the report ignored what he called "objective facts" and urged Washington to stop issuing the annual assessment.

The Pentagon report is "not beneficial to the improvement and development of Sino-US military ties," Geng was quoted as saying by the official Xinhua News Agency.

Issued this week, the report said secrecy surrounding China's military buildup increased the potential for misunderstanding and conflict with other countries.

It said China was developing more advanced weapons systems and pursuing the construction of aircraft carriers and ballistic missiles capable of attacking flat tops more than 930 miles (1,500 kilometers) away.

Those developments were helping shift the balance of forces with rival Taiwan in Beijing's favor, the report said. China claims the self-governing island as its own territory to be recovered by force if necessary.

The report, and Beijing's angry response, is just the latest source of friction in what has been a difficult year for relations between their militaries.

Beijing suspended contacts with the US military in January in protest over a $6.4 billion arms sale to Taiwan, and has hotly criticized US actions in the South China Sea and Yellow Sea, where joint US-South Korean naval drills are planned.

Meanwhile, China's more assertive stance on territorial issues and its soaring defense spending have sparked concern among its neighbors and at the Pentagon, which says Beijing needs to do more to explain the reasons behind its buildup.

In his response, Geng accused the US of unduly questioning Chinese military developments and exaggerating the threat against Taiwan.

"China's military development is reasonable and appropriate, and is aimed to protect its national sovereignty, security and territorial integrity, as well as keep apace with the rapid military development in the world," the spokesman said.