Japanese Prime Minister Shinzo Abe has vowed to join forces with the US to take action against North Korea after Kim Jong-un's regime launched its third missile in as many weeks.

North Korea fired at least one short-range ballistic missile that landed in the sea off its east coast, the latest in a fast-paced series of missile tests defying world pressure and threats of more sanctions.

The missile was fired on Monday from the region of Wonsan in an easterly direction into the Sea of Japan, South Korea's military said.

Abe said on Monday: 'As we agreed at the recent G7, the issue of North Korea is a top priority for the international community.

'Working with the United States, we will take specific action to deter North Korea.'

Earlier today it emerged that North Korean leader Kim Jong Un supervised the test of a new anti-aircraft weapon system

South Koreans at a railway station in Seoul watch a television broadcasting a news report on North Korea firing what appeared to be a short-range ballistic missile on Monday

The Japanese leader vowed his country will make utmost efforts to protect its people, while staying in close touch with South Korea and other countries.

The rocket was believed to be a Scud-class ballistic missile and flew about 450 km (280 miles), South Korean officials said. North Korea has a large stockpile of the short-range missiles, originally developed by the Soviet Union.

Monday's launch followed two successful tests of medium- to long-range missiles in as many weeks by Pyongyang, which has been conducting such tests at an unprecedented pace in an effort to develop an intercontinental ballistic missile (ICBM) capable of hitting the mainland United States.

Kim Jong-un has tested Scud-type short-range missiles many times in the past, most recently in April, according to U.S. officials. However, experts say it may be trying to test new capabilities that may be fed into its efforts to build an ICBM.

The state news agency boasted the system would 'completely spoil the enemy's wild dream to command the air'

'There are many possibilities ... It could have been a test for a different type of engine. Or to verify the credibility of the main engine for ICBM's first stage rocket,' said Kim Dong-yub, a military expert at Kyungnam University's Far Eastern Studies department in Seoul.

Modified versions of the Scud have a range of up to 1,000 km (620 miles).

On Tuesday, the United States will test an existing missile defence system to try to intercept an ICBM, the first such test, officials said last week.

Monday's launch was immediately reported to President Moon Jae-in, who called a meeting of the National Security Council, the South Korean office of the Joint Chiefs of Staff said in a statement.

The North Korean State News Agency said the system would soon be deployed throughout the country

The US Pacific Command said the short-range missile, launched from near Wonsan Airfield, was tracked for six minutes until it landed in the Sea of Japan.

It was not deemed a threat to North America. The command said it was working on a more detailed assessment of the missile launch.

'We continue to monitor North Korea's actions closely,' PACOM said in a statement.

'US Pacific Command stands behind our ironclad commitment to the security of our allies in the Republic of Korea and Japan,' it added.

The USS Carl Vinson has been deployed to the region, along with the USS Nimitz and USS Ronald Reagan supercarriers

It comes after reports emerged that the United States is sending a third aircraft carrier to the western Pacific region in an apparent warning to North Korea.

The USS Nimitz, one of the world's largest warships, will join two other supercarriers, the USS Carl Vinson and the USS Ronald Reagan, in the western Pacific, the sources told VOA.

The move is extremely rare for the US military, who rarely send three aircraft carriers to the same region.

Earlier on Monday it emerged that North Korean leader Kim Jong Un supervised the test of a new anti-aircraft weapon system and ordered its mass production and deployment throughout the country, after weeks of defiant ballistic missile tests.

The North has been pushing to develop a wide range of weapon systems since early last year at an unprecedented pace including a long-range missile capable of striking the mainland United States.

In recent weeks tested its intermediate-range ballistic missile, making some technical advances.

North's KCNA news agency did not report the exact nature of the weapon or the time of the test but said it was organised by the Academy of National Defence Science.

The ANDS is a blacklisted agency that is believed to be developing missiles and nuclear weapons.

This release from Korean Central News Agency shows the new weapons system being fired

The reclusive state rejects U.N. and unilateral sanctions by other states against its weapons programme as an infringement of its right to self defense and says the programme is necessary to counter U.S. aggression.

It last conducted a ballistic missile test a week ago. The United States denies any intention to attack the North.

KNCA said: 'Kim Jong Un ... watched the test of a new type of anti-aircraft guided weapon system organized by the Academy of National Defence Science.

'This weapon system, whose operation capability has been thoroughly verified, should be mass-produced to deploy all over the country.'

The system will 'completely spoil the enemy's wild dream to command the air, boasting of air supremacy and weapon almighty.'

The guided missile system is supposed to be a deterrent for U.S. air superiority

The new weapon comes after weeks of North Korean ballistic missile tests

KCNA said Kim was accompanied by his military aides and listed the three men believed to be the top officials in the country's rapidly accelerating missile programme.

They are Ri Pyong Chol, a former top air force general; Kim Jong Sik, a veteran rocket scientist; and Jang Chang Ha, the head of the Academy of National Defence Science, a weapons development and procurement centre.

North Korea said last Monday that it had successfully tested what it called an intermediate-range ballistic missile that met all technical requirements and could now be mass-produced, although outside officials and experts questioned the extent of its progress.

On Tuesday, the head of the U.S. Defense Intelligence Agency said that if left unchecked, North Korea is on an 'inevitable' path to obtaining a nuclear-armed missile capable of striking the United States.

Appearing at a Senate hearing, Defense Intelligence Agency Director Vincent Stewart declined to offer a time estimate but Western experts believe the North still needed several years to develop such a weapon.