WASHINGTON - U.S. President Barack Obama has been briefed on the shooting in Ottawa and is awaiting a chance to discuss it with Prime Minister Stephen Harper.
A spokesman for the president began today's daily White House briefing with a reference to events in Canada, which he called a valued friend and partner.
Josh Earnest said U.S. government officials have been in close touch with their Canadian counterparts.
He says they're trying to arrange a phone call between the president and the prime minister, at Harper's earliest availability.
The North American Aerospace Defence Command says it's taken steps so that it could respond, should there be any incidents involving aviation.
Down the street from the White House, on Pennsylvania Avenue, the Canadian Embassy says it's not been placed in lockdown, as suggested in some news reports.
A spokeswoman for the embassy says that, following news of the shooting, staff there simply locked the embassy's front door.
The shooting around Parliament has become the top news story in numerous countries.
All the main American news networks are offering live coverage; it's also the lead item on the best-known newspapers in a number of countries including the U.S., the UK, Mexico, France and Italy.
Even in Turkey — which borders an active war zone where an international coalition is fighting Islamist rebels — the Canadian events are now a top news item.
In CNN's coverage, a recurring question that a host has kept asking guests is: How did a gunman manage to walk into Canada's Parliament?
One U.S. law-enforcement analyst says this incident will prompt the same kind of scrutiny that occurred when a knife-wielding man recently jumped the fence to enter the White House.