Tokyo ? Japan sizzled through its hottest day on record Thursday as a heat wave claimed at least 13 lives and threatened power supplies strained by a recent earthquake, authorities and media reports said.

The mercury hit 105.6 degrees in the western city of Tajimi and the central city of Kumagaya, breaking a previous national record of 105.4 degrees set in 1933, the Meteorological Agency said.

In the Hachioji region of Tokyo, temperatures reached 101.7 degrees, breaking the previous record of 101.3 degrees for August.

The average high temperature in central Tokyo for the month of August is 87.4 degrees.