China's military denounced the United States and Australia on Wednesday for upgrading military ties, warning that such moves could erode trust and fan Cold War-era antagonism.

Chinese Defence Ministry spokesman Geng Yansheng made the warning about a plan unveiled in mid-November by U.S. President Barack Obama and Australian Prime Minister Julia Gillard to form a de facto base in north Australia for up to 2,500 U.S. Marines.

Geng's comments came on the same day Australian Foreign Minister Kevin Rudd was reported as backing the formation of a security pact with India and the United States, another step that could fuel China's worries of being fenced in by wary neighbours.

Military alliances are a product of history, but we believe any strengthening and expansion of military alliances is an expression of the Cold War mentality, Geng said in answer to a question about the U.S.-Australian announcement, according to a transcript on the ministry's website (www.mod.gov.cn.).

This is not in keeping with the tide of the era of peace, development and cooperation and does not help to enhance mutual trust and cooperation between countries in the region, and could ultimately harm the common interests of all concerned, he said.

We hope that the parties concerned will do more that is beneficial to the peace and stability of the Asia-Pacific region, and not the contrary.

But the Chinese spokesman indicated that Beijing was not shunning Washington. Chinese and U.S. defence officials, led by Under Secretary of Defence Michele Flournoy, will hold talks in Beijing next Wednesday, Geng told the briefing.

Earlier this month, Obama told Asia-Pacific leaders that the United States was here to stay, announced the plans to set up the de facto military base in north Australia and chided China for trying to prevent discussion of its South China Sea territorial disputes at regional forums.

The Chinese Ministry of Defence is the public mouthpiece of the People's Liberation Army (PLA), but foreign reporters are not allowed to attend its briefings.

COOPERATION OR CONFRONTATION?

Although falling short of full-throated condemnation of the U.S.-Australian move, Geng's words were tougher than earlier reaction from China's Foreign Ministry, which said Washington and Canberra should focus on cooperating with Beijing.

Geng said the idea raised by U.S. and Australian officials of advancing integrated air and sea combat amounted to trumpeting confrontation and sacrificing others' security for the sake of one's own security.

Chinese President Hu Jintao has made clear that he wants to avoid repeating the rifts that soured ties with Washington in the first half of 2011. Hu retires from power late next year, when the U.S. is focused on its presidential race, making China's leaders especially reluctant to risk distracting rows.

Beijing is also still licking its wounds from last year, when loud maritime disputes with Japan, Vietnam, the Philippines and other neighbours fanned suspicions about China's intentions.

Chinese military officers have, however, sometimes taken a tougher stance on security worries than civilian officials.

Earlier this week, PLA Major General Luo Yuan, well-known for his hawkish views, warned that Obama's regional push showed that the United States wanted to encircle China.

The comments from Australian Foreign Minister Rudd could also magnify such fears among Chinese observers.

A new trilateral pact bringing in India into a U.S.-Australian security tent was worth exploring because from little things big things grow, Kevin Rudd said in an interview with the Australian Financial Review newspaper.

The response from the Indian government has really been quite positive, said Rudd.

The idea of an Australian, Indian and U.S. trilateral security dialogue, in part to counter China's rising might, has been pushed by a trio of think-tanks in all three countries, but has yet to be adopted by any government.

At a briefing in Beijing, Foreign Ministry spokesman Hong Lei did not comment directly on Rudd's statement.

China hopes that countries in the region will do more to promote regional peace, stability and development, Hong said in answer to a question about the proposal.

India's Foreign Ministry did not comment on Rudd's statement. But Indian analysts said Delhi was likely to be cool on the idea, partly out of reluctance to risk riling China.

The Indian political establishment has always been wary of the idea of a military alliance, said Uday Bhaskar, the head of the National Maritime Foundation, a New Delhi-based think tank.

(Additional reporting by Rob Taylor in Canberra, Matthias Williams in New Delhi; Editing by Paul Tait)