US Defence Secretary Robert Gates has voiced concern over China's latest hi-tech weaponry and called for an improvement in uneasy military relations with Beijing to help defuse tension.
Speaking to reporters on his way to Beijing for three days of talks, Mr Gates said China appears to have made more progress in building its first stealth fighter jet than previously thought, and that an anti-ship missile posed a potential threat to the US military.
'They clearly have the potential to put some of our capabilities at risk. And we have to pay attention to them, we have to respond appropriately with our own programmes,' Mr Gates said.
But he said the advances in weaponry underlined the importance of building a dialogue with the Chinese military.
Mr Gates added that he hoped his visit would lay the ground for deeper defence ties with Asia's rising power.
'My hope is that, through the strategic dialogue that I'm talking about, that maybe the need for some of these capabilities is reduced,' Mr Gates said.
With Chinese President Hu Jintao due in Washington for a state visit on 19 January, both sides are anxious to show progress in defence ties, which China has repeatedly suspended over US arms sales to Taiwan.
'It's pretty clear the Chinese wanted me to come before President Hu visits Washington,' Mr Gates said.
'My own view is a positive constructive, comprehensive relationship between the United States and China is not just in the mutual interests of the two countries, it's in the interest of everybody in the region and I would say across the globe.'
Days before the US defence chief's trip, photographs appeared showing a prototype of China's first stealth fighter, the J-20, at an airfield in the southwest.
'We knew they were working on a stealth aircraft,' Mr Gates said when asked about the warplane.
'What we've seen is they may be somewhat further along in the development of that aircraft than our intelligence had predicted,' he said.
But he added 'there is some question about just how stealthy' the new fighter really is.
Mr Gates also said he had been concerned about China's pursuit of 'anti-ship, cruise and ballistic missiles ever since I took this job' four years ago.
He also said the development of China's anti-ship missile was at an advanced stage, but it is unclear whether the weapon was fully operational.
The Pentagon chief will meet Mr Hu and his Chinese counterpart, General Liang Guanglie, as well as visit the army's Second Artillery Corps headquarters outside of Beijing, which is China's nuclear command centre.
The talks were also expected to cover recent tension on the Korean peninsula, including China's role in helping to ease a recent crisis that began after the North shelled a South Korean island.
