The decree signed by Putin bans and restricts agricultural products from any country that is involved in imposing economic sanctions on Moscow. The document cites "national interests" the reason.
A final list of Western goods was being drafted and prepared for signing, government spokeswoman Natalya Timakova said.
The Itar-Tass news agency reported that Russian officials will hold talks with representatives from Ecuador, Brazil, Chile and Argentina on increasing food imports.
The Kremlin already announced bans on beef products from Romania and live animals from parts of Bulgaria, Greece and Italy. It halted some agricultural imports from Poland last week on health grounds.
The retaliatory measures come as the US and European Union's toughest sanctions yet come into force, targeting directly for the first time the Russian economy - its banks, its defense and energy sectors.
The economic tit-for-tat came as escalating violence in the area around the Malaysia Airlines crash site prompted an international forensic team to suspend their work recovering the remains of the 298 victims on board flight MH17 when it was shot down last month.
Dutch Prime Minister Mark Rutte said the 100-member team from the Netherlands, Australia and Malaysia would return to the scene when their safety was no longer threatened.
Concerns about Russia's intentions mounted as NATO claimed that Moscow was amassing some 20,000 soldiers along the border, which could perhaps be sent into Ukraine under the pretext of a peacekeeping mission.
NATO Secretary General Anders Fogh Rasmussen was set to meet Ukrainian leaders Thursday in Kiev for crisis talks.
In Stuttgart, Germany, US Secretary of Defense Chuck Hagel also referred to the alleged growing Russian threat. Russia was challenging the US "in ways we've never quite been challenged before," he told US troops in Stuttgart.
The US and Europe have already exerted illegal sanctions against Moscow under claims through which Russia is supplying arms to separatists in Ukraine, including surface-to-air missiles alleged to have brought down the Malaysia Airlines plane on July 17.
Russia strongly denies having supplied the rebels and has rejected any culpability in the crash.
NJF/NJF