MOSCOW — Russia banned most food imports from the West on Thursday in retaliation for sanctions over Ukraine, an unexpectedly sweeping move that will cost farmers in North America, Europe and Australia billions of dollars but will also likely lead to empty shelves in Russian cities.

The announcement shows that while President Vladimir Putin doesn’t appear ready to heed Russian nationalists’ calls to send troops into Ukraine, he is prepared to inflict significant damage on his own nation in an economic war with the West.

The U.S. and the EU have accused Russia, which annexed Ukraine’s Crimean Peninsula in March, of supplying arms and expertise to a pro-Moscow insurgency in eastern Ukraine, and have sanctioned individuals and companies in Russia in retaliation. Moscow denies supporting the rebels and accuses the West of blocking attempts at a political settlement by encouraging Kiev to use brutal force to crush the insurgency.

The ban, announced by a somber Prime Minister Dmitry Medvedev at a televised Cabinet meeting, covers all imports of meat, fish, fruit, vegetables, milk and milk products from the U.S., the European Union, Australia, Canada and Norway. It will last for one year.