Strong M5.0, 5.1 quakes hit Nagano Prefecture in central Japan

TOKYO - Two strong earthquakes jolted Nagano Prefecture in central Japan on Saturday, with the first measuring a preliminary magnitude of 5.0 followed by another registering magnitude 5.1, the country's weather agency said.

The Japan Meteorological Agency warned of aftershocks on a similar scale over the next week or so. No tsunami warnings were issued.