TOKYO -- An earthquake with a preliminary magnitude of 6.1 struck off the coast of Kushiro in Japan's Hokkaido on Saturday, local weather agency said.

The temblor occurred at 5:37 pm local time (0837 GMT), originating at a depth of approximately 20 km, said the Japan Meteorological Agency (JMA).

While slight changes in sea level may be observed along Japan's coastline, there is no concern for significant damage or a tsunami, the JMA said.

Emergency services are monitoring the situation closely, and no immediate reports of injury or structural damage have been issued.