The Russian government says it was not involved in the decision that has essentially halted the import of Ukrainian goods.
The Russian cabinet's press service said on August 15 that the decision to tighten import regulations was made by the country's customs service.
On August 14, the Ukrainian Federation of Employers announced that Russia's customs service had included all Ukrainian importers on its list of unreliable suppliers.
Russia's customs service has refused to comment to RFE/RL about the increased inspections, which have left millions of dollars worth of Ukrainian goods stuck at the border.
Ukrainian Prime Minister Mykola Azarov said on August 15 that the problem was related to the formation of the customs union uniting Belarus, Kazakhstan, and Russia.
Moscow has been urging Kyiv to drop its pursuit of European Union free-trade deals in favor of joining its Eurasian Customs Union.
Based on reporting by Interfax, UNIAN, and RFE/RL's Ukrainian Service