In a move largely seen as political retaliation, Russia has announced it will turn away U.S. beef and pork imports unless the U.S. can certify them as containing no residue of ractopamine, a feed additive used to promote lean-meat production. The ban will take effect this Friday, according to a report from Nasdaq.

Last week, the U.S. Senate passed a bill to establish permanent normal trade relations with Russia by a vote of 92 to 4. The bill, however, contains provisions for sanctions against Russian officials accused of human rights violations. According to news reports, some U.S. exporters and analysts believe Russia’s action on ractopamine is in retaliation over the human-rights provisions in the bill.

Earlier this year, U.S. trade officials negotiated a dispute with Taiwan over its ban on beef from cattle fed ractopamine. In September, Taiwan agreed to internationally accepted and scientifically established residue levels and dropped the ban.