A spokesman for the Red Lake Indian Reservation in (the U.S. state of) Minnesota says the community is in shock after a high school student shot dead nine people and then killed himself during Monday's shootout at a local school.

Red Lake Ojibwa Nation Chairman Floyd Jourdain says school security officials "did everything they could" when the student stormed the school but said the situation was beyond their control.

Law enforcement officials say the student first killed his grandfather and his grandfather's wife at their home. He then went to school where he shot dead a security guard, a teacher and several students.

Witnesses say the student --whom authorities have not yet identified-- waved his gun and grinned before walking into a classroom where he shot several victims. Police said the student later killed himself after exchanging gunfire with local police.

The rampage Monday afternoon was the deadliest school shooting since the 1999 Columbine High School massacre in Colorado left 14 students dead.