MONTREAL -- The federal government announced strict new measures on Thursday to ban most high-powered lasers around airports and in Canada's three largest cities due to the dangers they pose when pointed at aircraft.

Transport Minister Marc Garneau announced new interim measures that prohibit anyone from possessing a battery-operated hand-held laser over one milliwatts outside a private residence without a legitimate purpose, such as for work or education.

The restrictions, which enter into effect immediately, apply to municipalities within the greater Montreal, Toronto and Vancouver areas, as well as within 10 kilometres of any Canadian airport or heliport.

Transport Canada reported 379 incidents of lasers pointed at planes in 2017, most of which occurred in Ontario and Quebec.

That's down from 590 in 2015 and 527 in 2016 -- the year Garneau launched a public awareness campaign aimed at stopping the practice.

So far this year, there have been 63 laser incidents between January and April 30, including six at Montreal's Pierre Elliott Trudeau airport within a two-day span in February.

Despite the decreasing frequency of incidents, Garneau said more needed to be done to stop the practice.

"These dangerous attacks continue to happen far too often, more than once a day, in all corners of the country," he told reporters in Montreal.

"One laser strike is one too many."

Garneau said shining a laser into the cockpit of an aircraft can instantly blind or distract the pilot during a crucial moment of the flight, generally when the plane is taking off or landing.

While there have been no documented instances of aircraft accidents involving lasers in Canada so far, Garneau said that even a few seconds of distraction and blindness could have a "catastrophic effect" on the pilot's ability to land in a safe manner.

Pilots have described a blinding green light that fills the entire cockpit, causing distraction, flash blindness and even long-term vision damage, according to Dan Adamus, the president of the Air Line Pilots Association of Canada.

"We have talked to a couple of pilots who have spent two or three days seeing lights over the next few days (following a laser incident), so it's very serious," he told the news conference.

Those convicted of deliberately targeting aircraft can be punished with fines reaching $100,000, up to five years in prison, or both.

However, Garneau acknowledged that very few people are prosecuted due to the difficulty of catching them in the act.

Accordingly, the new measures include the possibility of handing out fines on the spot to anyone possessing a laser in violation of the rules.

Now, any individual caught with a hand-held laser in a prohibited zone without a reason can be immediately fined up to $5,000, while a corporation can face up to $25,000.