It appears that CBC's Toronto headquarters may have been on a list of alleged targets of at least one member of a group arrested last weekend on terrorism-related charges.

Police haven't named the buildings supposedly targeted, but a lawyer for one of the 17 people facing charges says his client is accused of wanting to storm and capture the CBC's Canadian Broadcasting Centre.

That came as news to Fred Mattocks, who is responsible for security contingency plans at the CBC building, which straddles a full block from Front Street to Wellington Street in downtown Toronto.

"I didn't know that," he says. "I'm a little shocked by that. We do have plans which contemplate action against this building. It's obviously easily identified and well known."

Mattocks says the security plans will be re-evaluated, but he doubts the building was in immediate danger.

"I think if the authorities knew of any clear and imminent threat to the CBC, we would have been advised," he says.

"We weren't, so I presume this plan was just that, a plan."

Across the street from the CBC building is the Toronto office of Canada's spy agency, the Canadian Security Intelligence Service, by some accounts a possible bomb target. Nearby are such crowd-drawing attractions as the CN Tower, the Rogers Centre and the Air Canada Centre.

Even more sensationally, the lawyer, Gary Batasar, says his client is accused of wanting to blow up the Parliament Buildings and behead Prime Minister Stephen Harper.

Harper won't comment, saying the matter is before the courts.

There have been breaches of security before in Ottawa.

In 1989, a bus with passengers aboard was hijacked and driven onto Parliament Hill, but the incident ended peacefully.

Ontario's Community Safety Minister, Monte Kwinter, says the alleged plot is a wake-up call.

"Certainly all police services, all municipalities, all commercial enterprises, as a result of this particular situation, have become very, very aware that there are some security problems that have to be evaluated, and that's going to be happening," he says.

Security experts say informing public institutions they might be targets could jeopardize police investigations.

At the same time, increasing security means less access for the public.

So it's all a delicate balancing act — one which security experts say Canada has had very little experience with.