A US Navy warship fired a missile at a failing spy satellite orbiting 130 miles above the Earth's surface today.

In the first mission of its kind, the US Navy struck the satellite with its first attempt but it is not yet known whether its hazardous fuel tank was destroyed.

President George Bush made the decision to shoot down the 5000lb USA 193 satellite, which is about the size of a small bus, after scientists predicted that about half the satellite would survive its descent through the atmosphere.

It has small rocket thrusters loaded with toxic hydrazine fuel, which can cause seizures, and long-term exposure can damage the liver, kidney and reproductive organs.

The missile attempt was approved by the president out of concern that the toxic fuel on board could crash to earth.

The Pentagon said the USS Lake Erie, armed with an SM-3 rocket designed to knock down incoming missiles, launched the attack this morning.

It hit the satellite as the spacecraft travelled at more than 17,000mph.

The Pentagon said: "Due to the relatively low altitude of the satellite at the time of the engagement, debris will begin to re-enter the earth's atmosphere immediately."

The government organised hazardous materials teams to be flown to the site of any dangerous or otherwise sensitive debris that might land in the United States or elsewhere.