The self-declared nuclear power North Korea has continued its missile tests this year after a four-week break.

According to neighboring countries South Korea and Japan, North Korea fired a suspected ballistic missile towards the open sea on Sunday.

UN resolutions prohibit the country from testing such missiles, which, depending on the design, can also carry a nuclear warhead.

North Korea had already conducted seven missile tests in January, including a medium-range missile that could also hit the US Pacific island of Guam.

South Korea had feared North Korea could resume missile testing after the end of the Winter Olympics in Beijing this month.

South Korea's National Security Council expressed deep regret and "serious concern" over the latest test after an emergency meeting.

put pressure on the US

The test came amid the escalating Ukraine conflict.

Experts have been speculating for a long time that North Korea could possibly use the conflict to put more pressure on the United States to submit concrete proposals for new negotiations.

The US government's talks with Pyongyang over its nuclear weapons program have been at a standstill for three years.

During Sunday's test, the missile was fired east from Sunan, near the capital Pyongyang, according to the General Staff of South Korea's armed forces.

Japanese Defense Minister Nobuo Kishi said the missile appeared to have flown 300 kilometers at an altitude of up to 600 kilometers.

She fell into the sea outside of Japan's "exclusive economic zone".

According to Kishi, the government in Tokyo lodged a protest against the missile test through the Japanese embassy in Beijing.

Tokyo and Pyongyang do not have diplomatic relations.

Again and again provocations

After testing an intermediate-range missile at the end of January, South Korean President Moon Jae-in warned that North Korea was getting closer to breaking its April 2018 self-imposed test ban on nuclear tests and ICBM tests.

North Korea's ruler Kim Jong Un indicated in January that such attempts could be resumed.

With the test of a medium-range missile, North Korea had gone beyond the previous weapons tests this year.

The country had previously tested short-range ballistic missiles, cruise missiles and, according to its own statements, hypersonic missiles that can fly at more than five times the speed of sound.