Chinese military experts have warned of an expanding arms race in outer space as Beijing and other rival powers seek to counter US ambitions to dominate the heavens.
The United States and other Western nations have criticised China's efforts to build a presence in space, especially a test in January 2007 when it shot down one of its own aged satellites.
But in a book issued by the state-run China Arms Control and Disarmament Association, two People's Liberation Army experts said Washington's bid for enduring security domination in outer space was pressing Beijing and other powers into competition, even confrontation.
"Strategic confrontation in outer space is difficult to avoid. The development of outer space forces shows signs that a space arms race to seize the commanding heights is emerging," wrote Wu Tianfu of the Second Artillery Corps Command College. The Corps controls China's nuclear arsenal.
"We can say that weaponisation of outer space. . . is already unstoppable."
Chinese diplomats have repeatedly said they want stronger international rules to avoid an expensive and destabilising arms race in space. But the PLA analyses suggest that at least some in China's military take a bleak view of prospects for such efforts and believe their country must get ready for escalating rivalry.
"In the not too distant future, outer space will certainly become a stage for struggle between countries," wrote Xu Nengwu of China's National Defence Science and Technology University. He nonetheless called for urgent efforts to halt the weaponising of space.
"The shared ideals or moral norms needed to bring about co-operation in outer space security are very difficult to form in a short time," Xu added.
The warnings came in an annual assessment of global trends issued by the Chinese arms control association, which appeared in local bookstores recently. They add to intensifying exchanges between Beijing and Washington over space ambitions.
Last month, Chinese President Hu Jintao publicly backed Russian opposition to US plans to set up a missile defence system that would include bases in eastern Europe.
But Pentagon officials have justified their own efforts to strengthen US space security by pointing to China's activities.
Beijing is "aggressively" honing its ability to shoot down satellites along with other space and counter-space capabilities, Army Brig. Gen. Jeffrey Horne of the US Strategic Command told a Congressional panel last month.
Horne said the United States must "proactively protect our space capabilities".
Among arms makers eyeing US space efforts are Lockheed Martin, Boeing and Northrop Grumman.
Wu, the Chinese military expert, said his country was the victim, not the perpetrator, in the conflict.
"Dominated by the idea of absolute domination of outer space, a major power is making a big fuss about space domination, creating rivals and provoking confrontation," Wu wrote.