North Korea's firing of a missile over northern Japan on Tuesday heightened concerns among citizens, triggering alerts in communities and prompting some to run for cover.

"The alert told me to evacuate, but I couldn't think of any building in the town that could withstand missiles. I didn't know where to go," said Ichiro Kondo, a 38-year-old fisherman in the town of Erimo in Hokkaido, said to be in the direct path of the missile.

A 59-year-old elementary school teacher in nearby Aomori Prefecture said he heard an "eerie" howl over the community's disaster radio network and switched on the television to find that the government had issued a warning.