Japanese Defense Minister Gen Nakatani ordered the Defense Ministry on Saturday to consider U.S. forces' offer of help amid the ongoing disaster in the Kyushu region.

The United States said it is prepared to extend support to Japan following a series of powerful earthquakes in Kumamoto Prefecture and other areas in the country's southwest, State Department spokesman John Kirby said Friday.

"We stand ready" to provide any and all assistance that the Japanese government may require, though Washington has yet to receive such a request from Tokyo, Kirby told reporters.

A series of strong earthquakes since late Thursday, including one with a preliminary magnitude of 7.3 — an equivalent to the 1995 quake that devastated Kobe and claimed over 6,000 lives — continued to jolt a wide area of the Kyushu region, centering on Kumamoto Prefecture, preventing Japanese authorities from grasping the scale of damage yet such as the number of victims and building collapses.

The U.S. government is monitoring the situation surrounding the devastation caused by the quakes and is "in touch with authorities in Japan," Kirby said.

The U.S. government and military mounted large-scale disaster relief "Operation Tomodachi" after the Tohoku region was hit by mega-earthquake and tsunami in March 2011.

Kumamoto quake info: where to go, how to help