TOKYO, Sept. 6 (CGTN) -- At least 120 people were injured and 19 others were missing after a Magnitude 6.9 earthquake rocked Japan's northern island of Hokkaido at 3.08 a.m. local time on Thursday (1808 GMT Wednesday), NHK reported.

The tremor struck at an approximate depth of 40-kilometers. No Tsunami warning was issued.

Massive landslides have damaged many houses in the quake-hit area.

Hokkaido's power companies said the quake has left 2.95 million buildings across Hokkaido prefecture without electricity.

The Tomari nuclear power plant on the island has lost its external power source but the operator said the nuclear fuel is currently being cooled by an emergency power supply system, NHK reported.

New Chitose Airport, the main airport of Sapporo in Hokkaido, canceled all domestic and international flights scheduled for Thursday.

All rail services have been suspended after the quake, including Shinkansen bullet trains.

Some local municipalities, including Sapporo, have canceled all classes at elementary and junior-high schools, according to education authorities in Hokkaido.