North Korea said on Monday it had successfully test-fired a new type of medium- to long-range ballistic missile the previous day, claiming further advancement in a weapons programme it is pursuing in violation of United Nations resolutions.

North Korea fired the ballistic missile into the sea early on Sunday, the first test of U.S. President Donald Trump's vow to get tough on an isolated North Korean regime that tested nuclear devices and ballistic missiles last year at an unprecedented rate.

The North's state-run KCNA news agency said leader Kim Jong Un supervised the test of the Pukguksong-2, a new type of strategic weapon capable of carrying a nuclear warhead.

North Korea has conducted five nuclear tests, including two last year, although its claims to be able to miniaturise a nuclear weapon to be mounted on a missile have never been verified independently.

KCNA said the missile was fired at a high angle in consideration of the safety of neighbouring countries. A South Korean military source said on Sunday the missile reached an altitude of 550 km (340 miles).

It flew a distance of about 500 km, landing off its east coast, towards Japan.

North Korea said the missile was propelled by a solid fuel engine, which follows last year's test of what it said was a solid-fuel powered, submarine-launched missile.

Solid fuel engines boost the power of ballistic rockets and give them greater range. They also provide less warning of an impending launch because it takes less time to fuel the rocket.

The test verified a "feature of evading interception" and "the mobility and operation of the new type missile launching truck", KCNA reported.

The North's two most recent missile tests were in October. Both were of intermediate-range Musudan missiles and both failed, according to U.S. and South Korean officials.

PROVOCATION EXPECTED

A U.S. official said at the weekend the Trump administration had been expecting a North Korean "provocation" soon after taking office. The United States would consider a full range of options in response but they would be calibrated to show U.S. resolve while avoiding escalation, the official said.

The latest test came a day after Trump held a summit meeting with Japanese Prime Minister Shinzo Abe, and also followed Trump's phone call last week with Chinese President Xi Jinping.

Abe described the test as "absolutely intolerable" and said North Korea must comply with U.N. Security Council resolutions.

In brief comments standing besides Abe in Palm Beach, Florida, Trump said: "I just want everybody to understand, and fully know, that the United States of America is behind Japan, our great ally, 100 percent."

Trump and his aides are likely to weigh a series of possible responses, including new U.S. sanctions to tighten financial controls, an increase in naval and air assets in and around the Korean peninsula, and accelerated installation of new missile defence systems in South Korea, the administration official said.

However, the official said that, given that the missile was believed not to have been an ICBM and that Pyongyang had not carried out a new nuclear explosion, any response would seek to avoid ratcheting up tensions.

Kim said in his New Year speech the North was close to test-launching an ICBM and state media have said such a launch could come at any time.

Once fully developed, a North Korean ICBM could threaten the continental United States, which is about 9,000 km (5,500 miles) from North Korea.