Russia ordered the closure of four McDonald's restaurants in Moscow on Wednesday after government health inspectors declared the U.S.-based fast food chain was serving contaminated products.
Rospotrebnadzor, the Russian state consumer protection agency, said "numerous violations" of the country's sanitary regulations had been uncovered during an inspection launched this week of McDonald's outlets in Moscow.
In a statement, Rospotrebnadzor said it would transfer "materials" gathered during the inspection to Russian law enforcement agencies.
American fast food outlets have been feeling the heat in Russia this year as relations between the two countries have become increasingly strained by the crisis in Ukraine.
Wendy's, the third-largest American hamburger chain, last month abandoned its Russian operations after falling out with Wenrus, its Russian franchisee.
According to Wendy's, Wenrus had not shown enthusiasm for expanding the business in Russia, which opened three years ago with an ambitious growth agenda.
McDonald's has faced a slew of attacks from Russian health inspectors this year but has pledged to soldier on in a nation where it says it serves more than 1 million customers a day in its 400 outlets.
Rospotrebnadzor signaled Wednesday that more trouble may be brewing for McDonald's as it pledged to continue the inspection of its Moscow stores. Among the four restaurants targeted for immediate closure is the McDonald's on Pushkin Square that was opened as the Soviet Union fell apart in 1991. It was the first American fast food outlet in Russia.
Although wildly popular in the early days, McDonald's has gradually lost its exotic image in Russia and has had to fight to hold its own against rivals entering the market, including Burger King, Subway and Papa John's Pizza.
Russian inspectors say their complaints about McDonald's are not motivated by politics. But there is no doubt that the iconic American burger chain has faced an unprecedented challenge from authorities here as relations between Moscow and Washington have plunged to depths not seen since the Cold War.
After Russia annexed Ukraine's Crimea region in March, McDonald's abandoned its franchises on the Black Sea peninsula, citing problems caused by the suspension of local banking services.
That argument did not convince Vladimir Zhirinovsky, firebrand leader of the nationalist Liberal Democratic Party of Russia, who immediately called for a boycott of McDonald's 400 Russian outlets.
In July, McDonald's was hit with a lawsuit by food inspectors in the Russian town of Novgorod who claimed the fast food giant had misrepresented the amount of fat and other ingredients in its burgers. In a separate attack, Rospotrebnadzor accused McDonald's of violating health and safety codes in some of its burgers and ice creams.