North Korean leader Kim Jong-un has hailed a submarine-launched ballistic missile test as a "great success" that gave his country "one more means for powerful nuclear attack".

Key points: State media says the North now has ability to strike Seoul, United States

State media says the North now has ability to strike Seoul, United States Kim Jong-un "monitored" submarine-launched ballistic missile test

Kim Jong-un "monitored" submarine-launched ballistic missile test South Korea says the launch on Saturday appeared to have failed

South Korea says the launch on Saturday appeared to have failed The apparent test was a violation of UN Security Council resolutions, Western nations say

The United Nations Security Council has condemned the test and expressed serious concern that such activities contributed to Pyongyang's development of nuclear weapons delivery systems.

"The members of the Security Council agreed that the Security Council would continue to closely monitor the situation and take further significant measures in line with the council's previously expressed determination," the council said in a statement.

South Korea's Defence Ministry said the launch on Saturday appeared to have failed as the missile, fired from a submarine in the Sea of Japan, flew just 30 kilometres.

But the North's state-run KCNA news agency insisted that the test, which it said was personally monitored by Mr Kim, was "another great success".

"It fully confirmed and reinforced the reliability of the Korean-style underwater launching system and perfectly met all technical requirements for carrying out ... underwater attack operation," KCNA said.

It cited Mr Kim as saying that Pyongyang "is now capable of hitting the heads of the South Korean puppet forces and the US imperialists anytime as it pleases".

The US Strategic Command said it had detected and tracked a North Korean submarine missile launch but it did not pose a threat to North America.

State Department spokesman John Kirby said launches using ballistic missile technology were "a clear violation of multiple UN Security Council resolutions".

On Sunday, the council called on states to implement sanctions on North Korea, particularly the measures adopted in March.

"The members of the Security Council emphasized that the DPRK's development and testing of new ballistic missile capabilities, even if launches are failures, is clearly prohibited by these resolutions," the council said.

France called on the European Union to unilaterally adopt additional sanctions on North Korea if the missile launch was confirmed.

Nuclear fears ahead of party congress

North Korea has been pushing to acquire submarine-launched ballistic missile (SLBM) capability that would take its nuclear strike threat to a new level, allowing deployment far beyond the Korean peninsula.

The isolated country has conducted a number of what it says were successful SLBM tests, but experts question the claim, suggesting Pyongyang had gone little further than a "pop-up" test from a submerged platform.

Tension has been running high on the Korean peninsula since Pyongyang's fourth nuclear test in January and rocket launch a month later widely seen as a disguised ballistic missile test.

Kim Jong-un says North Korea now has the ability to strike Seoul and the United States.

The UN Security Council responded by slapping its strongest sanctions to date last month.

Pyongyang has since staged a series of short- and mid-range missile tests, claiming it had acquired significant technical breakthroughs in its nuclear strike capability.

The latest launch comes amid concerns North Korea might conduct a nuclear test or a missile launch ahead of a key ruling party meeting in May, the first in 36 years.

AFP/Reuters