A missile fired from a US warship has destroyed a faulty spy satellite in orbit 247km above the Pacific Ocean.
The SM3 missile was launched from the cruiser USS Lake Erie in an effort to prevent the satellite's fuel tank, containing a reserve of the toxic fuel hydrazine, from crashing to Earth.
The imaging spacecraft, catalogued as US 193, was launched for the US National Reconnaissance Office from Vandenberg Air Force Base, California, in December 2006.
It malfunctioned shortly after launch, and its orbital decay has been monitored internationally ever since.
A senior Pentagon official said all indications were that the mission was a complete success. The missile appeared to have destroyed the fuel tank. 'We will need some time to confirm the extent of destruction, but it looks good,' he said.
Officials had earlier insisted the satellite would be shot down to stop it from tumbling to Earth and potentially posing a risk to humans.
But the operation had raised concerns elsewhere that the US was trying to test an anti-satellite weapon, amid rising global tension about the militarisation of space.
Critics pointed out that an average of one of the 17,000 pieces of space debris currently in orbit makes re-entry each day, and that many of those contain toxic material.
They said the US government was using the hydrazine as an excuse to shoot the satellite down.
Russia and China have expressed concern, though in January 2007 China intentionally shot down one of its own aging weather satellites using a modified ballistic missile.
The Russian Defence Ministry said the firing might have been used as a cover to test a new space weapon.
Nuclear and other weapons of mass destruction are banned from space under a 1967 international treaty, but Washington's plans have caused concerns about non-nuclear arms in space.
