The last of the United States' most powerful nuclear bombs is being disassembled today, nearly half a century after it was put into service at the height of the Cold War.

The final components of the B53 bomb will be dismantled at the Pantex Plant near Amarillo, Texas.

It is the only nuclear weapons assembly and disassembly facility in the US.

First put into service in 1962, the B53 weighed 4,536kg (10,000lb) and was the size of a minivan.

According to the American Federation of Scientists, it was 600 times more powerful than the bomb dropped on Hiroshima.

The National Nuclear Security Administration said the completion of the B53 programme's dismantling is a year ahead of schedule.

It is also in line with President Barack Obama's goal of reducing the number of nuclear weapons.