President Bush has expressed sorrow over a deadly shooting spree on a Native American reservation in the U.S. state of Minnesota.

In his radio address Saturday, Mr. Bush said action must be taken to avoid another tragedy like the one Monday at the Red Lake Indian reservation. A 16-year-old killed nine people - including his grandfather and students at his school - before committing suicide.

Mr. Bush said federal authorities are working to coordinate relief efforts. He noted that he phoned the chairman of the tribe to express sorrow. His comments Saturday were his first public remarks on the shooting.

In the radio address, Mr. Bush also marked the Easter holiday, and praised the military for "keeping the United States secure and advancing liberty in the world."