The principal of Columbine High School has offered his condolences to the families of the victims killed during a school shooting in Newtown, Connecticut.
"It's a reminder of how vulnerable we are as a society," he said.
"As a society we have to come together, we have to stop these senseless deaths." reports the Denver Post.
More top news
Groups of dairy farmers have milked supermarket shelves dry across the country in a protest against falling prices.
Seasonal rains have battered the country since late June with more than 150,000 people affected by floods and landslides.
The bus reportedly hit a tree near Russell Square.