A support group for children with cancer in Fukushima on Friday confirmed the diagnosis of a boy who at the time of the 2011 nuclear disaster was 4 years old, contradicting the prefectural government's view that no child that age had been diagnosed with thyroid cancer.

The boy underwent surgery after the diagnosis and after taking part in a survey to gauge the impact of the disaster. Local authorities, however, claim his cancer hadn't been officially confirmed at the time of the survey as we was still under observation.

The prefectural survey found that of the 385,000 people aged 18 or younger during the disaster, a total of 184 between the ages of 5 and 18 were diagnosed with or are suspected of having thyroid cancer.