Parents of four children killed when their kindergarten bus was engulfed by the March 11 tsunami filed a lawsuit Wednesday against the school in Ishinomaki, Miyagi Prefecture, seeking compensation for its failure to ensure the children's safety.

The suit is likely the first of its kind questioning the responsibility of schools with respect to evacuation guidance after the twin disasters, the plaintiffs' lawyer said. The parents are demanding ¥260 million in total compensation from Hiyori kindergarten and its principal at the time.

The complaint filed with the Sendai District Court said the school bus carrying 12 children left the kindergarten, which was located on high ground, about 15 minutes after the massive earthquake on March 11 for their homes along the coastline — despite a tsunami warning having already been issued.