A huge plume of smoke from the blast

It has effectively ended the former Soviet republic's capacity to test and launchi nuclear weapons.

The test site, which covers 85,000 square kilometres (32,800 square miles), was once the world's largest nuclear testing ground.

The Kazakh National Nuclear Centre worked with the US Government for the last five years to destroy silo launchers for intercontinental missiles.

Semipalatinsk

Site was 85,000 square kilometres(32,800 square miles) 470 nuclear tests over 40 years 100 tests above ground 118 tunnels and 13 bore holes closed

Other nuclear weapons at the Semipalatinsk nuclear testing grounds in northern Kazakhstan were also dealt with.

Between 1949 and 1989, the Soviet Union set off 470 nuclear explosions at the testing grounds.

More than 100 of the tests took place above ground.

Babies without hands

Our correspondent says Semipalatinsk was so secret during the Soviet era that it did not appear on the map and even the local population did not know what was taking place there.

Deformed babies were abandoned by parents

Although the area is sparsely populated, people living downwind more than 100 miles away have suffered from the fallout of nuclear tests.

Locals were not warned about possible ill effects of radiation, and stories abound of babies without hands, adults with cancerous growths and dogs without fur.

The joint Kazakh American effort, organised under the international Comprehensive Nuclear Test Ban Treaty, closed 118 tunnels and 13 boreholes at the test site.

It was ordered shut down in 1991.