The move was taken on orders from President Vladimir Putin in response to sanctions imposed on Russia by the West over the crisis in Ukraine. The ban has been introduced for one year.
Medvedev said that Russia is also considering banning Western carriers from flying over Russia on flights to and from Asia, a move that would significantly swell costs and increase flight time. He said the decision on that hasn't been made yet.
The US and the EU have accused Russia, which annexed Ukraine's Crimean Peninsula in March, of fomenting tensions in eastern Ukraine by supplying arms and expertise to a pro-Moscow insurgency, and have imposed asset freezes and loan bans on a score of individuals and companies.
Russia depends heavily on imported foodstuffs, most of it from the West, particularly in the largest and most prosperous cities such as Moscow. Food and agricultural imports from the US amounted to USD 1.3 billion last year, according to the US Department of Agriculture, and in 2013 the EU's agricultural exports to Russia totaled 11.8 billion euros (USD 15.8 billion).