Beijing - China on Thursday accused the United States of displaying a "Cold War mentality" in a new Pentagon military report and said it had lodged a formal protest with US officials.

"The report issued by the United States continues to play out the theory of China's military threat, severely distorts facts and interferes with China's internal affairs," Foreign Affairs Ministry spokesman Qin Gang said of the document, which pointed to "much uncertainty" raised by China's military build-up.

"We urge the US side to respect the fundamental facts and drop its Cold War mentality and bias ... [so as] not to further damage Sino-US relations," Qin told reporters.

"China has always followed the path of peaceful development and pursues a national defence policy which is defensive in nature," he said.

The Pentagon's annual report to Congress on Wednesday said China was rapidly upgrading its capability to conduct nuclear, cyber- and space warfare.

It said the Chinese military build-up poses troubling questions because Beijing has not clarified its intentions and does not publicly reveal all of its defence spending.

"Much uncertainty surrounds China's future course, particularly regarding how its expanding military power might be used," the report said.

China's Foreign Affairs Ministry on Thursday also criticized a US congressional resolution marking the 30th anniversary of the Taiwan Relations Act, under which the United States pledged to defend the island that China's ruling Communist Party still regards as a breakaway province.

Since Washington switched its formal diplomatic recognition from Taiwan to the People's Republic of China in 1979, the act has required the United States to help Taiwan to defend itself although Washington would not necessarily intervene if China attacked the island. (dpa)