A heat wave had killed at least six people and hospitalized more than 1,500 others across the nation Saturday as a three-day weekend got underway, a Kyodo News tally showed.

The deaths occurred in six prefectures: Toyama, Shizuoka, Tottori, Hiroshima, Oita and Kumamoto, which saw temperatures between 33.5 and 37.4. Elsewhere, Kyoto, Gifu and Mie prefectures saw the mercury top 38.

Osaka led the way with 156 people hospitalized for heat exhaustion, followed by 125 in Aichi and 102 in Chiba and Tokyo.

In Shizuoka, a man in his 90s who was found lying outside his home was confirmed dead at a hospital. Another senior, 86, died at a hospital after collapsing near his home.

In Okayama, where more than 1,000 volunteers showed up to help clean up flooded houses and remove debris caused by torrential rain and mudslides, at least 48 people were treated for heat-related maladies.

Of the Meteorological Agency's 927 observation points nationwide, 613 logged highs of at least 30, and 161 logged temperatures over 35.

The agency warned that temperatures will remain high throughout the week.