The death toll from a series of earthquakes and aftershocks in Japan earlier on Saturday has risen to 23 the number of injured continues to climb from the current 2,100.

Some 240 rounds of aftershocks have been rocking Japan almost non-stop after a series of quakes measuring as high as 6.8 on the Richter scale struck the nation over several hours on Saturday, centering around Ojiya, about 160 miles northwest of Tokyo.

Japanese weather officials say the aftershocks are likely to continue throughout the week and have not ruled out the possibility of another magnitude-6 trembler rattling the nation in the coming days.

Japan is among the world's most earthquake-prone countries. A magnitude-6 quake can cause widespread damage to homes and other buildings if centered in a heavily populated area. The government has estimated that about 7,000 people could die if such a powerful quake hit the Tokyo area.