There is no evidence so far that a gunman who attacked Canada's parliament had links to Middle Eastern Islamist extremists, the government has said.
Foreign Minister John Baird told the BBC gunman Michael Zehaf-Bibeau was "certainly radicalised", but was not on a list of high-risk individuals.
Zehaf-Bibeau killed a soldier at Ottawa's war memorial before being shot dead in the nearby parliament building.
Police have released video showing how the gunman stormed parliament.
It has also emerged that Prime Minister Stephen Harper hid in a cupboard in parliament for about 15 minutes during Wednesday's attack as MPs sharpened flagpoles to use as spears against the gunman.
Mr Baird told the BBC there were no substantiated claims yet that Zehaf-Bibeau was associated with Islamic State.
Mr Baird said he was "tremendously concerned about the number of Canadians who are radicalised and are fighting in Syria or Iraq, but we don't have any evidence to link the two at this stage".
"Reports suggest that well in excess of 100 Canadians have gone to fight jihad in the Middle East and that's a huge concern," he said.
Mr Baird also said Zehaf-Bibeau could have done much more damage than he did.
"For several minutes it was complete horror, complete terror, we didn't know whether the door was going to be kicked in, whether there was one or a group of people," he said.
Daniel Lang, chairman of the Senate national defence and security committee, told the BBC: "It was an ordeal I would not recommend anybody endure - there was just a wall's difference between where we were and where they were."
He said the incident had "shown our vulnerability and the reality that life here has changed dramatically".
Mr Lang said most parliamentarians had been calling for greater security and "this event proves there should be".
More details have emerged of the attack.
One source told the Globe and Mail that MPs had flanked the doors of their meeting room, preparing to attack the gunman with sharpened flagpoles.
"These guys were up there holding these spears ready to impale anyone who came in," the source said.
Mr Harper was placed in a cupboard - described as little more than a "cubbyhole" in the Centre Block after the gunfire rang out, the report said.
The video released by police shows various phases of Wednesday's attack.
The gunman is first shown hijacking a minister's car, then speeding off towards Centre Block, pursued by police.
At Centre Block he left the stolen car and ran into the building, exchanging gunfire with House of Commons security officers and Royal Canadian Mounted Police (RCMP) officers.
He was ultimately shot dead by Sergeant-at-Arms Kevin Vickers, a former senior RCMP officer, who received a standing ovation in parliament on Thursday when he resumed his duties.
'We are sorry'
Zehaf-Bibeau's mother, Susan Bibeau, told the Associated Press that she had lunch with her son last week - their first meeting in five years.
She said her son seemed lost and "did not fit in".
"Can you ever explain something like this?" she said. "We are sorry."
At a news conference on Thursday, RCMP Commissioner Bob Paulson said Zehaf-Bibeau was not linked to the Muslim convert who on Monday killed a Canadian soldier in Quebec in a hit-and-run attack.
However, Zehaf-Bibeau was trying to get a passport to travel to Syria.
Mr Paulson said: "I think the passport figured prominently in his motives."
- Michael Zehaf-Bibeau, 32, a petty criminal with a history of convictions for minor drug offences and theft
- Although officials have described him as a Muslim convert, community leaders in Canada say he was raised a Muslim
- One friend he met at a mosque described him as unstable while another told Reuters he had wanted to join Islamic State (IS) in Syria
- Zehaf-Bibeau was staying at a homeless shelter in Ottawa before the shooting
- His mother worked at Canada's Immigration and Refugee Board, his father is Libyan-born and may have fought against the regime of Muammar Gaddafi in 2011