North Korea said Friday it test-fired new tactical guided missiles a day earlier, confirming the launch of ballistic missiles for the first time in about a year.

On Thursday, South Korea's military said the North fired what appeared to be two short-range ballistic missiles into the East Sea, raising concerns that the missiles banned under the UN Security Council resolutions could sharply escalate tensions.

The latest launch came as the Joe Biden administration prepares to announce a new policy on the North.

"The newly developed new-type tactical guided projectile is a weapon system whose warhead weight has been improved to be 2.5 tons with the use of the core technology of tactical guided projectile that was already developed," the official Korean Central News Agency (KCNA) said.

The Academy of Defence Science conducted the launch and was "very successful just as it had been confidently predicted," according to the KCNA.

The two missiles "accurately hit the target" set in the water 600 kilometers off the East Coast, it said.

The KCNA added that the "reliability of the improved version of solid fuel engine was confirmed through several engine ground jet tests and their test-firing processes, and that the irregular orbit features of low altitude gliding leap type flight mode already applied to other guided projectile were also re-confirmed."

Observers say the North could have tested an upgraded version of its KN-23 missile, which resembles Russia's Iskander, showcased during a military parade in Pyongyang in January.

Photos released by state media show that the new tactical guided projectile has a conical warhead in black and white colors, similar to the one showcased during the military parade. The upgraded KN-23 missile in the parade had a conical warhead with a five-axle transporter erector launcher (TEL).

The North's Iskander is known to have a flight range of 400 to 600 km and mainly targets South Korea. Rather than following a general parabolic trajectory, the missile shows a more complicated path by doing a so-called pull-up maneuver over the course of its flight.

The solid-fueled missiles can be prepared to be launched in around 10 to 15 minutes.

Earlier, the Joint Chiefs of Staff said the two missiles were fired into the East Sea from the North's eastern town of Hamju at 7:06 a.m. and 7:25 a.m., and flew around 450 kilometers with an altitude of 60 km.

The launch was guided by Ri Pyong-chol, vice chairman of the Central Committee of the Workers' Party, officials of the Department of Munitions Industry of the Party Central Committee and senior officials in the sector of national defense scientific research.

However, North Korean leader Kim Jong-un did not oversee the missile testing, in an apparent move to pile up pressure on Washington in a toned-down manner.

The North also did not send a direct message to the US or South Korea, although Ri stressed that the weapons development "is of great significance in bolstering up the military power of the country and deterring all sorts of military threats existing on the Korean Peninsula."

Thursday's launches came four days after the country fired two cruise missiles into the Yellow Sea on Sunday.

The latest launch also came as the Biden administration was completing its North Korea policy review.

The US president said Thursday that the United States will "respond accordingly" if North Korea continues to escalate tensions, noting the launch of ballistic missiles was in violation of UN Security Council resolutions.

This marks the North's first launch of ballistic missile since Biden took office.

North Korea last fired a ballistic missile in March 2020.

The UN Security Council sanctions committee on North Korea is expected to meet Friday (Washington time) at the request of the US to discuss Pyongyang's latest launches.

The meeting will be at a lower level than the Security Council meeting held when the North last fired ballistic missiles a year ago.

The US earlier said it has tried to reach out to North Korea since mid-February but that Pyongyang has remained unresponsive. North Korea's first vice foreign minister, Choe Son-hui, has said her country will continue to ignore US overtures until Washington gives up its hostile policy toward Pyongyang.

Nuclear talks between Washington and Pyongyang have remained stalled since the 2019 summit in Hanoi between then US President Donald Trump and leader Kim ended without a deal. (Yonhap)