North Korean leader Kim Jong-un has vowed to achieve “equilibrium” in military force with the US.

He outlined the ambition as the United Nations Security Council strongly condemned Pyongyang’s latest “highly provocative” ballistic missile launch over Japan.

The missile, detected by the South Korean and US militaries, travelled 2,300 miles (3,700km) as it passed over the island of Hokkaido before landing in the sea.

It was the country’s longest test flight of a ballistic missile yet.

North Korea confirmed the missile was an intermediate range Hwasong-12, the same model launched over Japan on 29 August.

The launch followed Pyongyang’s most powerful nuclear test to date on 3 September and two July flight tests of intercontinental ballistic missiles (ICBM).

The increasing frequency of the tests have raised fears that the country is closer than ever to building a military arsenal that could viably target the US and its allies in Asia.

The state-run Korean Central News Agency said Mr Kim had expressed great satisfaction about the launch, which he said verified the “combat efficiency and reliability” of the missile.

He vowed to complete his nuclear weapons programme in the face of strengthening international sanctions, the agency reported.

Kim Jong-un purportedly watches the launch of a Hwasong-12 missile in this undated photo released by North Korea’s news agency (Reuters)

“As recognised by the whole world, we have made all these achievements despite the UN sanctions that have lasted for decades,” the agency quoted Mr Kim as saying.

He said the country’s final goal “is to establish the equilibrium of real force with the US and make the US rulers dare not talk about military option for the DPRK,” referring to North Korea‘s official name, the Democratic People’s Republic of Korea.

He indicated more missile tests would soon follow, saying all future drills should be “meaningful and practical ones for increasing the combat power of the nuclear force” prepared for ”actual war”.

Mr Kim said his country, despite “limitless” international sanctions, had nearly completed the building of its nuclear arsenal and called for “all-state efforts” to reach the goal and obtain a “capacity for nuclear counter attack the US cannot cope with”.

Photos published by North Korea‘s state media showed the missile being fired from a truck-mounted launcher and a smiling Mr Kim clapping and raising his fist while celebrating from an observation point.

It was the first time North Korea showed the missile being launched directly from a vehicle, which experts said indicated confidence about the mobility and reliability of the system.

In previous tests, trucks were used to transport and erect the Hwasong-12s but the missiles were moved onto separate firing tables before launch.

The UN Security Council accused North Korea of undermining regional peace and security by launching the missile over Japan. It said the nuclear and missile tests “have caused grave security concerns around the world” and threatened all 193 UN member states.

Prior to the launches over Japan, Pyongyang had threatened to fire a salvo of Hwasong-12s toward Guam, the US Pacific island territory and military hub that North Korea has called an “advanced base of invasion”.

The Security Council stressed in a statement after a closed-door emergency meeting that all countries must “fully, comprehensively and immediately” implement all UN sanctions.

Japan’s UN ambassador Koro Bessho called the missile launch an “outrageous act” that threatened global security.

He was joined by British, French and Swedish ambassadors in demanding all sanctions be implemented.

Calling the latest launch a “terrible, egregious, illegal, provocative reckless act”, Britain’s UN ambassador Matthew Rycroft said North Korea‘s largest trading partners and closest allies – a thinly veiled reference to China – must “demonstrate that they are doing everything in their power to implement the sanctions of the Security Council and to encourage the North Korean regime to change course”.

Videos capture moment Japan alert siren goes off following North Korea's missile launch

Friday’s launch followed North Korea‘s sixth nuclear test on 3 September, which the country said involved the detonation of a thermonuclear weapon built for its ballistic missiles.

In earlier tests, North Korea fired its Hwasong-12 and Hwasong-14 missiles at lofted angles to reduce their range and avoid neighbouring countries.

The two Hwasong-12 launches over Japan indicate North Korea is moving toward using angles close to operational to evaluate whether its warheads can survive the harsh conditions of atmospheric re-entry and detonate properly.

While some experts believe North Korea would need to conduct more tests to confirm Hwasong-12’s accuracy and reliability, others believe Mr Kim’s comments indicate the country could soon move toward mass-producing the missiles for operational deployment.

South Korean President Moon Jae-in, a liberal who initially pushed for talks with North Korea, said the tests made dialogue “impossible”.