In 1961 Russia conducted the biggest thermonuclear device called Tsar Bomba at its northern Novaya Zemlya archipelago with a yield of over 50 megatons.

May 12, 2010 (Hamsayeh.Net) - North Korean scientists have achieved a breakthrough in the country’s nuclear program by carrying out a successful nuclear fusion experiment, the Yonhap news agency reported on Tuesday.

The test involved a thermonuclear process, which would enable North Korea to ultimately build more powerful nuclear weapons known as hydrogen bombs. Six countries Russia, United States, United Kingdom, China, France and India are the ones that have so far tested thermonuclear devices. On October 30, 1961 Russia conducted the biggest thermonuclear device called Tsar Bomba at its northern Novaya Zemlya archipelago with a yield of over 50 megatons. A nuclear bomb that size would destroy a city  within a 40 km radius.

The North Korean report said, ‘Nuclear fusion is a breakthrough event that shows North Korea's cutting-edge technology that is leaping forward.’

Pyongyang has twice conducted nuclear tests and it’s now considered a nuclear weapons state. The United States, Japan and South Korea have put pressures on Pyongyang against its nuclear program for years. North Korea, however, successfully tested own nuclear bombs despite Washington’s long-held antagonism towards Pyongyang.