TOKYO (AFP) - A Japanese couple have been arrested for pulling a knife on a school principal who refused to reschedule a sports tournament their child had missed, according to the police and reports.

The bizarre incident allegedly happened after the husband and wife had repeatedly asked in vain that the school's annual sports day be put off to another date.

The situation escalated when Toshiaki Nabatame, 50, and his wife Yukiko, 49, threatened the principal and two teachers with a kitchen knife, the police and media reports said.

They were arrested this week in Ibaraki, north of Tokyo.

It was not clear why the child had not been able to participate in the originally scheduled tournament, which was held on Sunday.

The wife reportedly admitted to the police that she had threatened the teachers, but her husband denied the charge.