A strong earthquake struck off the northern coast of Japan on Monday, prompting authorities to issue a tsunami alert for parts of Hokkaido and nearby regions. The Japanese meteorological agency (JMA) said the quake measured magnitude 7.2 and occurred beneath the sea, with its epicentre located about 50 kilometres off the coast near Aomori city.The agency warned that the tremor could generate tsunami waves reaching up to three metres in the affected area, advising residents to remain alert and follow safety directions.Further details on damage or injuries were not immediately available. Authorities continue to monitor the situation as coastal communities respond to the alert.(With inpurts from agency)