BEIJING (AFP) - China hit back at the US on Thursday over a document that called Beijing's growing military a threat to Washington's armed dominance in Asia, accusing its authors of a "Cold War mentality".

China's military spending is soaring and the modernisation of the People's Liberation Army (PLA) "is altering the security balance in the Asia-Pacific, challenging decades of US military preeminence in the region", the US-China Economic and Security Review Commission said in its annual report on Wednesday.

Beijing's foreign ministry spokesman Hong Lei told reporters: "We hope this committee can stop this Cold War mentality and do things that can boost mutual trust between China and the US."

The Washington document said China was "rapidly expanding and diversifying its ability to strike US bases, ships and aircraft" throughout the Asia-Pacific, including areas it could not previously reach, such as the US Pacific territory of Guam.

Quoting the Office of Naval Intelligence, it said that China will probably have 313 to 342 submarines by 2020 - including around 60 that can fire intercontinental ballistic missiles or cruise missiles against ships.

At a regular briefing, Hong said China's military policy was "defensive in nature" and "within a reasonable range".

Its sole purpose, he added, was "protecting our country".

"China has always been an important force for peace and development in the Asia-Pacific," Hong said.

US President Barack Obama has pledged to "pivot" US foreign policy to pay greater attention to Asia in light of the rise of China, which has increasingly tense relations with US allies Japan and the Philippines over territorial disputes.

The commission called on Congress to fund shipbuilding to meet Obama's goal of stationing 60 per cent of US warships in the Asia-Pacific by 2020, up from 50 per cent.

The clearest symbol so far of China's growing naval capabilities is the country's first aircraft carrier, the refitted Soviet-era vessel Liaoning, which went into service last year.

Song Xue, deputy chief of staff of the PLA navy, said in April that "China will have more than one aircraft carrier".

The US has 11 aircraft carriers, included the recently christened USS Gerald Ford, though the ship remains under construction amid huge cost overruns and delivery has been postponed until February 2016.