In about 15 to 20 minutes, around 500 people abandoned the town to took refuge at the middle school. They witnessed what happened below with extreme terror.

Jin Sato, the magistrate of the town, was missing after the quake but later confirmed alive. He returned to his post Saturday and called for all-out efforts to save every life.

As rescue workers are racing against the time, the whole world put the focus on the nuclear incidents at the Fukushima No. 1 nuclear power plant in the quake-hit areas.

A hydrogen explosion occurred Monday morning at its No. 3 reactor while fuel rods at its No. 2 reactor were fully exposed later in the day after its cooling functions failed.

The nuclear plants shut down automatically due to Friday's massive earthquake, but the shortage of power and tsunami damage to back-up generators apparently crippled reactors' cooling systems.

Explosions created by "hydrogen bubble" blew apart the buildings housing the No. 1 and No. 3 reactors, but did not pierce the reactors' steel and concrete containment vessel.

After the blast at the No. 3 reactor, the Nuclear and Industry Safety Agency asked about 500 residents within a 20-kilometer radius to take shelter inside buildings.

Earlier Monday morning, Kyodo News Agency reported that the radiation level around the Fukushima plant has again exceeded the legal limit, but chief government spokesman Yukio Edano said Monday that radiation was at a tolerable level for humans.

While U.S. and Russian nuclear experts are rushing to Japan, it was reported that the latter has also asked the U.N. nuclear watchdog, the International Atomic Energy Agency, to provide experts in a joint effort to deal with the incidents at the nuclear power plant.