ANKARA

Japan on Monday urged its residents to stay alert for a possible "stronger" earthquake after more than 180 tremors were recorded near the country's southwestern Tokara island chain over the weekend, the Kyodo news agency reported.

According to the Japan Meteorological Agency, a quake measuring 4 on the Japanese seismic intensity scale of 7 occurred twice on Sunday and once early Monday on Akuseki Island in the island chain in Kagoshima prefecture.

Jolts with an epicenter near the island chain have been frequently observed since Saturday.