At least eight Japanese high school students were feared killed in an avalanche on Monday, 160 kilometers (100 miles) north of Tokyo.

The pupils were among a group of 52 students and 11 teachers from seven high schools who were on the slopes of Nasu Hot Spring Family Ski Resort in Tochigi prefecture when disaster struck.

The students, mostly from Otawara High School in Tochigi, were found without vital signs, an official with a prefectural disaster task force told news agency AFP.

In Japan, deaths in such circumstances are not announced officially until doctors can confirm them.

More than 30 people in the group were injured by the 9:20 a.m. avalanche while on a mountain climbing outing, authorities and local media said.

"This is an annual event and we never had a major accident before," one of the teachers told Jiji Press. "I am really shocked."

A warning for heavy snow and possible avalanches was in place from Sunday until Monday in the area north of Tokyo, with the local weather agency forecasting snowfall of 30 centimeters (about 12 inches). The ski season had ended at the resort, but some of its facilities were made available for the high school mountaineering trip organized by local physical education authorities.

An official told Agence France-Presse they still didn't know how many teachers are included among the victims. The "Asahi Shimbun" reported one student was still missing.

Prime Minister Shinzo Abe said in parliament the government "will make every effort to respond to the disaster, while making it a top priority to rescue victims" of the avalanche.

More than 100 troops were deployed to the slopes to help in the rescue effort at the request of the prefecture's governor. The "Asahi Shimbun" reported poor weather was preventing a helicopter from accessing the accident site.

aw/rc (dpa, AFP, AP)