Today’s shootings on Parliament Hill in Ottawa have reignited debate over security in Canada’s capital.

Most of downtown Ottawa was under lockdown for most of the day following two shootings, including one inside Parliament that sent MPs and staffers into lockdown.

The gunfire began shortly before 10 a.m., when a 24-year-old reservist with the Canadian Armed Forces was shot dead while standing on guard at the War Memorial.

Shortly after, shots rang out in the hallways of Parliament Hill’s Centre Block, where hundreds of MPs, including Prime Minister Stephen Harper, were holding their caucus meetings in adjacent rooms.

No one was caught in the line of fire, but some frightened MPs expressed concerned over public access to the Parliament buildings.

Liberal MP Marc Garneau said that though visitors go through metal detectors, most parliamentary offices are accessible once people have entered the buildings.

“Somebody who decides that they want to rush the building can walk up, rush in, show their weapon and then rush into the building before anybody can really effectively do anything,” Garneau said.

Independent Ontario MP Dean Del Mastro told CTV’s Power Play that he has raised concerns in the past about the screening process for visitors.

“I take no quarrel with the how quick the response on the gunman was in the building but it’s obviously very troubling that a gunman was able to get inside Canada’s Parliament building,” Del Mastro said.

The MP said it may be time to move security checkpoints to the “edges of the parliamentary precinct, so that when people enter onto the grounds itself, they’ve already been screened.”

NDP MP Charlie Angus said he hopes Parliament Hill remains an “open” place amid any possible changes to security.

"I just think what's really important to remember from this is that Parliament Hill is an incredible public place that's open for people to play football and come and protest and sit and have their lunches, do their yoga," he said.

“We can't lose that. We need to make it more secure, we need to make sure people can be safe ... but we can never lose sight (that it's) an open place where Canadians feel welcome.”

NDP House Leader Peter Julian echoed that sentiment, saying any additional security measures would need to take into account Canadians’ right to have access to their elected representatives and the “goings-on” in Parliament.

“Over the next few days we’re going to have to take a look at security measures and a number of other things,” Julian said. “But that doesn’t change the principle that we’re free, accessible and democratic and should remain so.”

Parliament’s experience with security breaches is limited. In 2009, environmental protesters managed to make it to the top of two buildings, but they were unarmed and posed no threat to personal safety. The incident did, however, prompt a serious security review by the auditor general, who found that several different security groups were responsible for Senate, House of Commons and Parliament Hill grounds.

Currently, there is more co-ordination and the government has been considering arming all security personnel rather than just some of them.

With files from The Canadian Press