A Japanese news agency has reported that radiation more than six-thousand times the standard level has been detected within the 20-to-30-kilometer radius of the Fukushima Number One nuclear power plant. It is the area where residents are required to take shelter indoors.

Kyodo News Agency cited the Japanese Science Ministry’s monitoring of radiation levels 21-kilometers from the Fukushima power plant on Tuesday and Wednesday. The radiation level of 330 microsieverts per hour was detected, which is some 66-hundred times the standard level.

The ministry’s survey was conducted using two gauges in three locations while riding motor vehicles. Levels inside the vehicles were slightly lower than those outside.

A ministry official said that radiation levels generally drop as recorded measurements are further removed from the source, but this investigation was an exception to the rule of distance and radiation levels due to the wind currents.