North Korea fired two ballistic missiles into the Sea of Japan on Thursday, Japan's Defense Ministry said, in the third such provocation by Pyongyang this week.

The launches, which occurred at 8:47 p.m. and 8:53 p.m., respectively, came as U.S. Vice President Kamala Harris visited South Korea, including a trip to the Demilitarized Zone on the border of the two Koreas, following her visit to Japan.

The missiles, launched from an area around the west coast of North Korea, traveled about 300 kilometers with a maximum altitude of 50 km before falling into waters off the country's east coast, according to Japanese Defense Minister Yasukazu Hamada.

Hamada told reporters that Japan lodged a protest with North Korea through a diplomatic channel in Beijing over the test-firings in defiance of U.N. Security Council resolutions, which ban Pyongyang from testing ballistic missile technology.

Earlier, Japanese government officials said the missiles appeared to have landed outside Japan's exclusive economic zone, and there were no immediate reports of damage involving aircraft or ships.

It marked the third provocation by North Korea this week, following a short-range ballistic missile launch on Sunday and two such launches on Wednesday.

Sunday's launch came after the United States and South Korea conducted joint naval exercises in the Sea of Japan for the first time in five years.

The two allies are set to hold a trilateral anti-submarine training with Japan on Friday.

The U.S. Indo-Pacific Command said it is aware of the two ballistic missile launches on Thursday, but has assessed that the event does not pose "an immediate threat" to U.S. territory or its allies.

While criticizing the "destabilizing impact" of North Korea's "unlawful" programs related to weapons of mass destruction, the military reaffirmed that U.S. commitments to the defense of Japan and South Korea remain ironclad.

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