<br/>A strong quake with a magnitude of 6.3 struck in the Pacific Ocean off northern Japan today, but no immediate damage was reported and no tsunami warning was issued. <br/> <br/>The US Geological Survey said the quake struck at a depth of 58 kilometres off the South Kuril islands, which are controlled by Russia but also claimed by Japan. Moderate shaking was also felt on Japan's northern Hokkaido island.<br/>