North Korea fired two ballistic missiles into the Sea of Japan, the first test since Joe Biden became the President of the United States.
Pyongyang is banned from testing ballistic missiles, which are considered threatening weapons, under UN Security Council resolutions.
Japan said no debris had fallen within its territorial waters.
It comes just days after North Korea fired two non-ballistic missiles into the Yellow Sea.
Japan’s Prime Minister Yoshihide Suga said on Thursday that the tests posed a threat to security and peace to his country as well as the region.
A statement from South Korea’s Joint Chiefs of Staff initially reported the launch of two “unidentified projectiles”.
On Tuesday Biden down played the non-ballistic missile launch which took place over the weekend, saying the US did not consider it as a provocation. Those short-range missiles were thought to be either artillery or cruise missiles, which are not banned under the UN Security Council resolutions on North Korea.
The tests come as the Biden administration continues to attempt to make diplomatic contact with North Korea.
Pyongyang has yet to acknowledge that Mr Biden is now in office, and the two countries remain at loggerheads over the North’s nuclear and ballistic missile programmes.
The current focus of the new White House team and its allies is the impending review on North Korea policy.
Decades of sanctions and three summits between former US President Donald Trump and North Korean leader Kim Jong-un have failed to prevent Pyongyang from developing a larger and more deadly nuclear arsenal.