Students and families were reunited in emotional scenes after the shooting at Arapahoe high school in Colorado.
A 15-year-old girl was in critical condition after the shooting, suspected to have been carried out by an 18-year-old, Karl Pierson, who police say apparently shot himself at the scene.
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Canada, Mexico, Australia, Argentina, Brazil, South Korea will also be free from the levies announced by Donald Trump.
Bolton is viewed with contempt by almost the entire foreign policy establishment in Washington.
A top temperature today of 13 Celsius (55F).