This summer saw 660 reported mountaineering accidents across Japan, the most on record, reflecting the mountaineering boom among middle-aged and older people, the National Police Agency said.

The figure is the highest since the agency began compiling comparable statistics in 1968. The figure covers accidents nationwide during July and August.

According to the NPA report, released Friday, 753 people were involved in mountaineering accidents, the second-highest figure following last year's 782.

By age bracket, people over 60 accounted for 46.7 percent of the cases, at 352. When included those in their 40s and 50s, the figure stood at 562, accounting for 74.6 percent.

Forty-eight people died or were listed as missing, while 357 were injured.

"Most of the accidents were caused by a lack of knowledge or physical strength," an NPA official said, urging people to climb in groups and to make plans based on their mountaineering skill and experience.

By prefecture, Nagano had the highest number of accidents at 107, followed by Shizuoka's 84 and Toyama's 62.