North Korea has reportedly added hydrogen bomb on its military arsenal, which could be a hundred times more powerful than an atomic bomb.
The claim was made by the country's leader Kim Jong Un but senior defense and intelligence officials said there is no evidence that they have such weapon.
During World War II, Hiroshima and Nagasaki were leveled by an atomic bomb.
Experts believed that North Korea may have been working toward a hydrogen bomb, also known as thermonuclear bomb, but the country may not have the capability to produce.
"They have not even conducted any single test and now they make this claim - there's no way for us to believe it is true," Zhang Liangui, a North Korea expert based at the China's Central Party School. He once studied at Kim II Sung University.
"Their purpose could be to pressure the international community. Their main aim is to demand the international community to recognize the country as a nuclear state, and to further stress they will not abandon the nuclear weapons," Liangui added.
Neighboring countries reacted with caution to the claims of the communist country.
"The situation on the Korean peninsula is very delicate, complex and fragile. We hope all concerned will make effort that contributes to peace and stability," Huan Chunying, Chinese Foreign Ministry spokeswoman, said in a report by NBC News.
"We are closely monitoring and tracking any and all of North Korea's nuclear activities. So far, we have not noticed any unusual movements or activities," South Korea's Defense Ministry said.
The White House is skeptic that North Korea was successful in developing a hydrogen bomb.
"At this point, the information that we have access to calls into serious question those claims, but we take very seriously the risk and the threat that is posed by the North Korean regime in their ambitions to develop a nuclear weapon," Josh Earnest, the White House press secretary, said in a report by The New York Times.
