On Thursday, North Korea is said to have tested two ballistic missiles, the first since Joe Biden took office as US president.
According to the Japanese Coast Guard, the robots were fired at 20-minute intervals and flew over 400 kilometers before landing in the Sea of Japan.
A high-ranking American official tells the news agency AP that these are two ballistic short-range robots.
Both Japan and South Korea have condemned the testing.
The UN Security Council has banned robot testing
In a comment, Japanese Prime Minister Yoshihide Suga said the firings threatened "peace and security in Japan and the region."
The bid administration has not yet commented on the incident.
The UN Security Council has previously banned North Korea from testing ballistic missiles.
Thursday's weapons test is the second in a short time.
On Wednesday, South Korea's military leadership stated that North Korea had fired an unidentified projectile at sea between the Korean Peninsula and Japan.
The USA then downplayed the weapons test as it must have been about cruise robots, which does not violate any rules.