North Korea has claimed it has developed a more advanced nuclear weapon that has "great destructive power".
Photos show the country's leader Kim Jong-un inspecting a hydrogen bomb that will be loaded on a new intercontinental ballistic missile.
The hydrogen bomb's power is adjustable to hundreds of kilotons and can be detonated at high altitudes.
Its indigenously produced components allow the country to build as many nuclear weapons as it wants, the North's official KCNA news agency said.
AdvertisementAdvertise with NZME.
The recent development comes amid heightened tension following Pyongyang's test launch of two missiles in July that potentially could hit major mainland US cities.
In the report about the new bomb, KCNA added: 'Kim Jong-un said he felt the pride at the indomitably bolstering up of [North Korea's] nuclear forces despite a great price as he watched the Juche-oriented thermonuclear weapon with super explosive power made by our own efforts and technology.
"He expressed great satisfaction over the fact that our scientists can do anything without fail if the party is determined to do.
"The scientists further upgraded its technical performance at a higher ultra-modern level on the basis of precious successes made in the first H-bomb test."
North Korea is increasingly putting world leaders on edge as the country continues to push its limits in regards to building up weaponry and firing off missiles.
On Monday, North Korea, which sees the exercises as preparations for invasion, raised the stakes in its stand-off with the United States and its allies by firing an intermediate-range missile over Japan.
Japan Prime Minister Shinzo Abe called the move an 'unprecedented' threat to his country.