A foreign ministry spokesman, while declining to confirm the incident, said other countries should not be alarmed.

"There's no need to feel threatened about this," Liu Jianchao told journalists.

"So far we have not got any confirmed information about this," he said, adding that China had no intention of triggering an arms race in space.

"We are not going to get into any arms race in space," he said.

Washington said China fired a missile to destroy an orbiting weather satellite last week, making it the third country after the United States and the former Soviet Union to shoot down anything in space.

If confirmed, the test would mean China could now theoretically shoot down spy satellites operated by other nations.

The ageing Chinese weather satellite was hit on January 11 US time and may have left considerable debris behind, a US official said.

The US magazine Aviation Week and Space Technology first reported a test, which was confirmed by the White House.

The magazine said the missile was fired from the Xichang space center in central Sichuan province and had destroyed a Chinese weather satellite that was launched in 1999.

The impact reportedly occurred more than 500 miles (800 kilometers) above Earth, high enough to hit orbiting satellites.

The White House was quick to condemn the reported test.

"The United States believes China's development and testing of such weapons is inconsistent with the spirit of cooperation that both countries aspire to in the civil space area," said national security spokesman Gordon Johndroe.

Japan, which has long been concerned at China's rapidly growing military spending, joined the United States in condemnation.

"From the view of the peaceful use of space and international security, we naturally have concerns about it," Chief Cabinet Secretary Yasuhisa Shiozaki, the government spokesman, told a news conference.

Japanese Foreign Minister Taro Aso said the test is "questionable from the viewpoint of peaceful use (of space) because there could be concerns of scattered debris," he said.

In Taiwan, which China considers a province awaiting reunification, defence ministry spokesman Wu Chi-fang said: "Any weapons developed by China would affect the security in the Taiwan Strait."

South Korea conveyed its concern, while Australia summoned China's ambassador.

"Our concern about this is that to have a capacity to shoot down satellites in outer space is not consistent with the traditional Chinese position of opposition to the militarisation of outer space," Australian Foreign Minister Alexander Downer said.

If confirmed, it would be the first case since the 1980s, when the United States and Soviet Union both destroyed satellites in space. The two superpowers ceased the tests largely because of the problem of debris.

But US President George W. Bush's administration has opposed international calls to end all tests, saying in a policy paper last fall that the United States had the right to "freedom of action" in space.

China had been a leading critic of Washington's policy on the military use of space, raising the possibility that the reported test was a calculated diplomatic strategy.

"The test was shocking for its symbolism," said Yasunori Matogawa, a professor of space engineering at the Japan's Institute of Space and Astronautical Science.

"China proved its deterrent power," he added, predicting that Japan could enter a race to catch up.

"It may fuel the argument that Japan should develop space technology for national defense, especially as it came in the midst of the North Korean nuclear crisis," Matogawa said.

China, which in 2003 became the third country to carry out a manned space mission, can now theoretically shoot down spy satellites operated by the United States, Japan, Russia, Israel and Europe, Aviation Week said.

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