South Korea's military on Monday said the North had fired an ICBM that used solid fuel, which makes missiles easier to transport and faster to fire than liquid-fuelled versions.

The launch was the third time the North had tested a solid-fuel ICBM, after launches in April and July, which analysts said signalled consistent efforts to improve the technology.

"A drill of launching ICBM Hwasongpho-18 was staged as an important military action to clearly show the DPRK's nuclear strategic forces' overwhelming counteraction will and matchless strength to the enemies," KCNA news agency said of the Monday launch, using the acronym of the North's official name.

The missile, the largest in North Korea's arsenal, flew just over 1,000 kilometres, it said, and demonstrated "the combat capability of ICBM unit".

Kim said the launch sent a "clear signal to the hostile forces" and "set forth some important new tasks for the development of the DPRK's nuclear strategic forces," KCNA added.

"The successful drill is a practical demonstration of the actual condition and reliability of the formidable striking capabilities and absolute nuclear war deterrent possessed by the DPRK's armed forces," the report cited Kim as saying.

The launch followed yet another bout of angry rhetoric between the US-South Korea alliance and the North.

The United States and South Korea on Friday held their second session of the Nuclear Consultative Group in Washington, where they discussed nuclear deterrence in the event of conflict with the North.

On Saturday, they warned that any nuclear attack from Pyongyang on the United States and South Korea would result in the end of the North Korean regime.

A spokesperson for North Korea's defence ministry on Sunday slammed the allies' plans to expand annual joint military exercises next year to include a nuclear operation drill, calling it "an open declaration on nuclear confrontation."

North Korea has carried out a record-breaking number of banned weapons tests this year, including last month's launch of a military satellite, which it claimed was providing images of US and South Korean military sites.

North Korea last year declared itself an "irreversible" nuclear power and has repeatedly said it will never give up its nukes programme, which the regime views as essential for its survival.

The United Nations Security Council has adopted many resolutions calling on North Korea to halt its nuclear and ballistic missile programmes since it first conducted a nuclear test in 2006.