SEOUL: North Korea fired two suspected ballistic missiles into the sea Thursday, in its first substantive provocation to the new US administration of Joe Biden.

The nuclear-armed North has a long history of using weapons tests to ramp up tensions, in a carefully calibrated process to try to forward its objectives.

Donald Trump’s first year in office was marked by a series of escalating launches, accompanied by a war of words between him and North Korean leader Kim Jong Un.

Pyongyang had been biding its time since the new administration took office, not even officially acknowledging its existence until last week.

But Seoul’s joint chiefs of staff said the North fired two short-range missiles into the Sea of Japan, known as the East Sea in Korea, from South Hamgyong province.

They travelled 450 kilometres and reached a maximum altitude of 60 kilometres, the JCS added, and after an emergency meeting South Korea’s National Security Council expressed “deep concern” at the launch.

North Korea is banned from developing any ballistic missiles under UN Security Council resolutions, and is under multiple international sanctions over its weapons programmes.