Canada will "never be intimidated" by terrorists who seek to bring "savagery" to the country's shores, Prime Minister Stephen Harper has said.

Speaking after a soldier was shot dead at the National War Memorial in Ottawa, Mr Harper said terrorists would find "no safe haven" in Canada.

"Let there be no misunderstanding - we will not be intimidated. Canada will never be intimidated," Mr Harper said.

"In fact, this will lead us to strengthen our resolve and redouble our efforts - and those of our national security agencies - to take all necessary steps to identify and counter threats and keep Canada safe here at home."

Canada will work with its allies to "fight against the terrorist organisations who brutalise those in other countries with the hope of bringing their savagery to our shores", he added.

Corporal Nathan Cirillo was guarding the National War Memorial when he was shot at point-blank range at around 10am local time on Wednesday.

Witnesses say the gunman raised his arms in triumph after the shooting, which led to a lockdown in downtown Ottawa, lasting until Wednesday night.

Authorities say federal government buildings remain off limits following the attack.

After firing upon Cpl Cirillo, the gunman entered Canada's nearby Parliament building where he was pursued by law enforcement officers.

People fled the building, took cover, or barricaded doors as police cordoned off the streets outside.

The Globe and Mail captured this footage of shooting within the parliament building:

Officials say 58-year-old sergeant-at-arms Kevin Vickers shot the attacker dead outside the MPs' caucus rooms.

At least three people were treated in hospital for minor injuries after the attack.

Police are investigating potential suspect Michael Zehaf- Bibeau, 32, who US agencies have been advised is a Canadian convert to Islam.

The shooting occurred two days after an Islamic convert ran down two Canadian soldiers near Montreal, killing one of them.

Mr Harper said the two terrorist attacks "are a grim reminder that Canada is not immune to the types of terror attacks we have seen elsewhere around the world".

The parliament complex in Canada's capital Ottawa remains on high alert after a gunman opened fire before being shot dead.

Police say there's no longer a threat to public safety and have removed blockades but their operation continues.

Originally posted at 7:17am