North Korea appeared to test fire a ballistic missile on Tuesday that may be more capable than the "hypersonic missile" it launched less than a week earlier, South Korea's military said, as Pyongyang pursues increasingly advanced weapons.

The launches underscored leader Kim Jong Un's New Year's vow to bolster the military with cutting-edge technology at a time when talks with South Korea and the United States have stalled.

Initial estimates found Tuesday's missile travelled more than 700 km to a maximum altitude of 60 km at a top speed up to 10 times the speed of sound (12,348 kmh), South Korea's Joint Chiefs of Staff (JCS) said in a statement.

"We assess that this is more advanced than the missile North Korea fired on Jan. 5, though South Korean and U.S. intelligence authorities are conducting detailed analysis," the JCS said.

The suspected ballistic missile launch was detected around 7:27 a.m. (local time) from North Korea's Jagang Province toward the ocean off its east coast, the same location as last week's test.

North Korea has joined a global race in developing hypersonic missiles, which are usually defined as weapons that reach speeds of at least five times the speed of sound - or about 6,200 kms per hour - and can manoeuvre at relatively low trajectories, making them much harder to detect and intercept.

Last week, South Korean military officials cast doubts on the capabilities of the hypersonic missile North Korea claimed to have test fired on Wednesday, saying it appeared to represent limited progress over Pyongyang's existing ballistic missiles.

"Today's test might be intended to send a message to the South after authorities here said the earlier test was a failure and did not involve a hypersonic missile," Kim Dong-yup, a former South Korea Navy officer who now teaches at Seoul's Kyungnam University.

'DESTABILISING'

South Korea's National Security Council held an emergency meeting where members expressed "strong regret" that the missile test came at a time when regional stability is extremely important, and urged North Korea to resume dialogue and cooperation, the presidential Blue House said in a statement.

The U.S. military's Indopacific Command (INDOPACOM) said while it had assessed that launch did not pose an immediate threat to the United States or its allies, it "highlights the destabilising impact of North Korea's illicit weapons program."

 READ MORE

• North Korea launches second hypersonic missile in fiery test
• North Korea has reportedly publicly executed at least 7 people for watching K-pop
• North Korea able to produce more uranium for bombs than previously thought
• Air force plane to help enforce sanctions on North Korea

Japanese Prime Minister Fumio Kishida noted the United Nations had just finished holding discussions on how to respond to last week's launch.

"That North Korea continues to launch missiles is extremely regrettable," he told reporters.

Tuesday's apparent launch came a day after the United States mission to the United Nations, joined by France, Ireland, Japan, the United Kingdom and Albania, issued a joint statement condemning last week's test.

"These actions increase the risk of miscalculation and escalation and pose a significant threat to regional stability," U.S. Ambassador Linda Thomas-Greenfield said in the statement on Monday. Such tests not only improve the North's capabilities, but expands what it can offer illicit arms clients and dealers around the world, she added.

U.N. Security Council resolutions ban all ballistic missile and nuclear tests by North Korea, and have imposed sanctions over the programmes.

However, China and Russia are pushing the U.N. Security Council to ease sanctions on North Korea by removing a ban on Pyongyang's exports of statues, seafood and textiles, and lifting a refined petroleum imports cap.

Thomas-Greenfield reiterated calls for countries around the world to enforce sanctions, and for North Korea to return to talks and abandon its missiles and nuclear weapons.

North Korea has said it is open to talk, but only if the United States and others drop "hostile policies" such as sanctions and military drills.

Few observers expect Kim to ever fully surrender his nuclear arsenal and North Korea argues its missile tests and other military activities are similar to measures taken by other countries.

Leif-Eric Easley, a professor of international studies at Seoul's Ewha University said North Korea is attempting to use repeated tests to normalise its missile capabilities and military programmes, portraying it as engaged in incremental improvements for self-defence like many other countries.

"At the same time, Pyongyang is challenging international sanctions, testing what it can get away with while the United Nations Security Council remains divided," he said.