OTTAWA -- Canada is standing firm against Russia in the face of retaliatory sanctions on Canadian food products, saying it will not be "intimidated" by the latest move by Vladimir Putin, despite the potential impact on pork producers.

Russia announced a year-long ban on food imports from Canada, the U.S. and other countries Thursday. Russian Prime Minister Dmitry Medvedev also threatened airspace retaliation.

The measures are aimed at meat, fish, milk and dairy products, fruit and vegetables from Canada, the U.S., the European Union, Australia and Norway, he said in Moscow.

"For a long time, Russia has not responded to the so-called sanctions declared against it by certain countries," Medvedev told a government meeting.

"Until the last moment, we hoped that our foreign colleagues would realize that sanctions lead to a blind alley, and that no one benefits from them. But they didn't realize this, and now we have been forced to respond."

Canada's pork producers are poised to take the biggest hit from the Russian sanctions. Canada's agricultural exports to Russia amounted to $563 million in 2012, according to Agriculture and Agri-Food Canada, mostly in frozen pork.

There are currently as many as 1,000 container loads of pork on ships bound for Russia, according to the Canadian Meat Council. They will have to be redirected.

"It becomes a huge concern for producers, because any time pork product backs up at the packers, that generally relates to a lower price paid to producers," said Karl Kynoch, chairman of the Manitoba Pork Council.

"Hopefully, with the good relationships that our packers have with other countries, they can ... redirect the pork product into other good markets sooner rather than later."

Industry Minister James Moore said the world needs to continue to "stand firm" against Russia, despite the escalation of sanctions.

"We will certainly look at the impact of these sanctions on the Canadian economy, but they will in no way cause us to have any hesitation in the principled position we've taken in opposing Vladimir Putin's regime," Moore said during a news conference in Montreal.

"We will not be intimidated by these kinds of tactics."

Officials in Ontario promised to support its pork producers in the face of the sanctions. The province exported $18 million in pork products to Russia in 2013.

"We have reached out to the Ontario pork sector, which accounts for the majority of our exports to Russia, to better understand how this will impact business," said a joint statement from Agriculture Minister Jeff Leal and International Trade Minister Michael Chan.

"Our government has a variety of risk management programs in place to assist producers in addressing income declines resulting from market events. ... We will continue working to ensure Ontario farmers are in a position to succeed."

The trade deal with the European Union could help ease the sting of the sanctions, Kynoch said.

"Trying to move agreements forward in the EU is very positive. The other positive thing is that Canada exports to about 80 some countries. Some of those are very small, but we do have access to a lot of other markets."

The Russian move was announced a day after Canada slapped new sanctions and travel bans on several top Russian and Ukrainian politicians and groups with ties to Putin's government amid reports that Russia is amassing thousands of troops along the Ukrainian border.

Putin retaliated by ordering authorities to draft a list of agricultural products from countries that have imposed sanctions on Russia.

Medvedev said Russia is also considering banning Western carriers from flying over Russia on flights to and from Asia -- a move that would significantly hike costs and increase flight time. He said a decision on that hasn't been made yet.

"I'd like to emphasize that all these measures are not being introduced yet, but otherwise can be implemented either separately or together. As a result, the expenses of Western airlines will grow significantly," he said.

Medvedev said Russia could also introduce restrictions regarding imports of planes, navy vessels and cars, but added that the government will realistically assess its own production potential.

Helicopters, airplanes and spacecraft are No. 2 on the list of top Canadian exports to Russia, according to Statistics Canada data, amounting to about $116 million a year.

Prime Minister Stephen Harper has frequently said Russia's occupation of the Crimean Peninsula and provocative military activity in eastern Ukraine is a "grave concern" to Canada and the world.

Harper said Canada is prepared to take further actions if Putin's government continues its military aggression.

With files from The Associated Press