South Korea's Institute of Nuclear Safety says it has discovered a patch of pavement in Seoul is emitting radiation at levels 10 times higher than normal.

The government-funded research institute says the radioactive pavement was identified during a field investigation Wednesday in the residential Wolgye-dong neighborhood.

The institute says the pavement is emitting radiation from cesium-137 at 10 times the normal background level. The institute says a more precise reading will be released in “three to five days” after further evaluation, but it stresses that the level detected is not dangerous to humans.

Cesium-137, with a half life of about 30 years, is among the radioactive isotopes released by the meltdown of three reactors at the Fukushima-1 Nuclear Power plant in Japan.

Cooling systems at the plant were destroyed by the magnitude 9.0 earthquake and tsunami which struck northeastern Japan on March 11.

Trace levels of radioactive cesium were detected as far away as North America following the disaster. It has also been previously measured globally, in tiny amounts, because the element was released into the atmosphere during atmospheric nuclear weapons tests by various countries over several decades.

The Institute of Nuclear Safety has previously reported that cesium-137 has been detected over the past 10 years in South Korea's air and soil when so-called yellow dust blows in from China .

Researchers say they are not yet able to determine why a significantly higher level of radioactive cesium has turned up in pavement in a residential area of the capital.