A gunman shot and fatally wounded a Canadian soldier standing guard at a war memorial in Ottawa on Wednesday, then entered Parliament, where numerous shots rang out according to officials. It is thought a Parliament Hill security guard was also injured in the attack. It is still unclear how many gunmen were involved.
Yesterday Canada raised its terror threat level from low to medium because of a rise in "general chatter" from radical groups.
A suspected Canadian militant ran over two soldiers in Quebec on Monday, killing one of them. This is what we know and do not know about today's events.
What we know
A soldier was shot and killed by a gunman when he was standing guard at the National War Memorial. His identity will not be confirmed until his family have been informed.
A suspected gunman was later shot dead inside Canada's parliament.
Police earlier said they were working on the assumption that there were multiple gunmen involved in the incidents. They have asked people to stay away from downtown Ottawa while the operation continues, and they have said the situation is ongoing. There is no one in custody at this time.
Canadian Prime Minister Stephen Harper was addressing a meeting of legislators from his Conservative party in parliament on Wednesday when an armed man burst into the building and ran right by the door of the room, a cabinet minister told Reuters.
All military personnel in Canada are being told to stay inside. They have been told not to wear their uniforms if they are not on active duty.
The city's parliament is on lockdown.
Others fled parliament by scrambling down scaffolding erected for renovations, witnesses said.
This video from Canada's the Globe and Mail shows the scene in parliament.
The US embassy is also on lockdown.
Stephen Harper, Canada's prime minister has released a brief statement
Earlier today there was an attack at the National War Memorial and on Parliament Hill. Our thoughts and prayers are with the families of those who were attacked. The Prime Minister is safe and not on Parliament Hill and being briefed by security officials. The police continue to do their important work and we are still gathering the facts.
The White House has said Obama was briefed on the event but the details remained "sketchy" and the US could not yet officially consider it to be an act of terrorism.
There are conflicting and unconfirmed reports about the number of shooters involved. Journalist Bruce Cheadle reports there were between two and three gunmen, and one was shot by the Canadian parliament's Serjeant at Arms.
The gunman, who was said to be carrying a rifle and wearing a a banadana, reportedly forced a driver out of their car after shooting a soldier and drove towards parliament, where more shots were fired. Reuters cites an eyewitness who claimed the gunman was chased by police into the centre block of parliament with 30 shots being fired inside the building.
CNN quotes Ottawa police spokesperson Marc Soucy who claimed there were "numerous gunmen" but only one person was shot.
Aside from the soldier, CBC Ottawa reports Ottawa has received three patients, two of whom are stable.
Josh Wingrove, a reporter for the Globe and Mail has tweeted he saw a body near the library of Parliament.
What we don't know
It is still unclear how many gunmen were involved, any motivation they might have had, and police have stressed the incident is ongoing.