A six-year-old boy was taken to hospital with serious injuries after being thrown from a small motor boat into the Ottawa River, along with a four-year-old girl and a 39-year-old man, according to Ottawa paramedics.

A witness with a boat rescued the trio from the waters near Britannia and brought them to shore around 12:15 p.m., paramedics said.

The boy had serious injuries to his torso from being thrown from the boat, as well as from the propeller, paramedics said. The girl was also taken to hospital with minor shoulder injuries, while the man had minor hand injuries, paramedics said.

"The two children were wearing life jackets at the time of the incident which both contributed greatly to their survival as well as minimizing injury and what could have certainly been a tragedy," paramedics said in a news release.