Tatsuya Aoki, a 21-year-old university student from Moriya, Ibaraki Prefecture, has become the youngest person ever to scale K2, the world's second-highest peak, his university said Wednesday.

His team member, Yuka Komatsu, 23, from Akita, is the first Japanese woman -- and the eighth woman ever -- to conquer the peak, Tokyo-based Tokai University said. The two reported reaching the summit Tuesday afternoon.

The 8,611-meter mountain is in the Karakoram Range on the border between Pakistan and China. It is considered the world's most difficult mountain to scale.

The university's six-member expedition, led by Yoshitsugu Deriha, decided to attempt K2 to commemorate the 50th anniversary of the founding of their alpine club.

According to the university, the expedition set up a base camp at 5,150 meters on June 20 and began the ascent from the south-southeastern ridge, slightly south of the ridge from which an Italian expedition became the first team to climb K2 in 1954.

Komatsu is the first woman, the university said, to reach the summit from the route the Japanese team took.

By surmounting snow and steep ice walls and the dangers of strong winds and falling rocks, the expedition reached a point at 7,900 meters known as the "Shoulder" on July 9. The team set up a camp to launch their assault on the summit from there, the university said.

The climb to the summit was marred by bad weather, but the climbers awaited their chance as expeditions from other countries retreated.

The two expedition members who made the summit Tuesday had never scaled a mountain higher than 8,000 meters before, the university said.