Foreign Ministry spokesman Liu Jianchao said China had briefed the US, Japan and other countries, which had expressed fears that the test could spark an arms race in space, and insisted that it "did not constitute a threat to any country."

"China has never, and will never, participate in any form of a space arms race," he said. Asked whether China had informed India about the test, Liu said he could not confirm but would check with relevant departments if New Delhi had been informed.

This is the first time that Beijing had publicly confirmed the satellite strike, apparently conducted on January 11. US officials, quoting spy satellite data, had released the news last week, putting pressure on Beijing to speak about the test.

Liu said the test "was not directed at any country and does not constitute a threat to any country."

"China stresses that it has consistently advocated the peaceful development of outer space and it opposes the arming of space and military competition in space," he told a crowded news briefing that was dominated by the missile test issue, which made global headlines.

Asked about the delay in confirming the test, Liu said, "China has nothing to hide. After various parties expressed concern, we explained this test in outer space to them."

Liu said countries had voiced worries about dangerous space debris and escalating military rivalry in space, but said such fears were groundless.

He said he had no information about a second test.

The test made China only the third country in the world -- after the US and the former Soviet Union -- to have the ability to shoot down an object in space.

Earlier reports from the US said that China shot down an ageing Chinese weather satellite by slamming into it a ground based ballistic missile about 860 km above earth. Experts say the test will put low orbiting American spy satellites vulnerable.

China is already a major space power, capable of launching manned space missions.

China launched its first manned space mission in October 2003, joining the US and Russia as the only nations to have performed such a complicated task.

The Communist giant has announced plans to allow a Chinese astronaut to perform a spacewalk as early as 2008 and hopes to send an unmanned probe to the Moon by 2010.