The detection of the dangerous ants, an invasive alien species in Japan, followed the first discovery of them in the country in Amagasaki, another city in the same western prefecture, late last month.

According to the ministry, fire ants, some 2.5-6.0 millimeters long each, have a powerful venom that could cause anaphylaxis, a serious full-body allergic reaction sometimes resulting in death.

"Despite its small size, a fire ant's bite causes pain as strong as a fire wound," the ministry said.

The Kobe municipal government set up a take force Sunday and decided to investigate whether there are more fire ants on the manmade island and thoroughly get rid of them if the insects are found.

On May 26, an importer discovered a colony of fire ants inside a container in Amagasaki that was shipped from a port in China's Guangdong Province. The importer exterminated the ants.

But the other ants were found in cracks in road pavements and other places in the yard on the island, where the container was stored before being sent to Amagasaki. (Jiji Press)