Moscow: The US Sunday called on Russia to lift restrictions on American meat imports.
The US said the new requirement on American beef and pork supplies contradicted Russia's obligations as a member of the World Trade Organization (WTO).
Russia, which joined the world trade club as its 156th member in August 2012 after 18 years of negotiations, announced Friday that beef and pork imports from US producers using ractopamine must be tested and certified free of the feed additive.
The move came a day after the US Senate repealed the Cold War-era Jackson-Vanik restrictions on trade with Russia and simultaneously passed the Magnitsky Act, which targets Russian officials deemed by Washington to have violated human rights.
"The US is very concerned that Russia has taken these actions, which appear to be inconsistent with its obligations as a member of the World Trade Organization," Agriculture Secretary Tom Vilsack and US Trade Representative Ron Kirk said in a joint statement.
"The US calls on Russia to suspend these new measures and restore market access for US beef and pork products."
Russian officials denied allegations that the decision to restrict US meat imports was made in response to US sanctions against Russian human rights abusers adopted in conjunction with the trade bill.
The Magnitsky Act specifically targets Russian officials considered by the White House to be involved in the death of Russian whistleblower lawyer Sergei Magnitsky in 2009, but it extends to other purported violators of human rights in Russia as well.