The crash in Canada's capital city between a double-decker bus and a Via Rail train occurred about 8:48am local time (1.48pm BST)
CBC News reports all of Ottawa's emergency responders are heading toward the scene.
All the dead and injured were on the bus, authorities said.
More top news
Police are issuing appeals for a gang who attacked two men after luring them into meeting with what they thought were underage girls.
Aston Villa came from behind to shock Liverpool at Wembley and book their place in the FA Cup final against Arsenal next month
The film appears to show the executions of Ethiopian Christians on the beach in Libya. It has not been verified.