North Korea has fired a missile that crossed over Japan, South Korean officials have confirmed. The missile flew over Hokkaido before eventually landing in the ocean.

Hokkaido is the second-largest island in Japan and is the northernmost part of the country.

BREAKING: Yonhap agency says South Korean military confirms North Korean ballistic missile flew over Japan. — The Associated Press (@AP) August 28, 2017

After flying over the island, the missile then broke into three pieces and fell into the ocean off of the coast of Hokkaido.

BREAKING: NORTH KOREA MISSILE BROKE INTO THREE PIECES, FELL INTO WATERS OFF JAPAN'S HOKKAIDO - NHK — Dan Murphy (@dan_murphy) August 28, 2017

The Japanese government had earlier sent out a notification urging people to evacuate to a "sturdy building or basement" after the missile was fired. It was unknown where, if anywhere, the missile was targeting.

Alarm from JP Gov. "A missile was fired from North Korea. Please evacuate to a sturdy building or basement." #northkorea #Japan pic.twitter.com/38NNCteqY2 — Chiho komoriya (@Chihokomoriya) August 28, 2017

This marks the first time North Korea has launched a missile over Japan since the late 1990s.

Japan's Chief Cabinet Secretary Yoshihide Suga said this was a "new, serious development" in the conflict with North Korea.