By Maria Kiselyova and Olga Sichkar

MOSCOW (Reuters) - McDonald's burgers and shakes may become the latest victims of worsening ties between Moscow and Washington after a Russian consumer watchdog agency accused the U.S. chain of sanitary violations.

McDonald's Corp , which opened its first Russian restaurant in Moscow in 1990, became an iconic symbol of flourishing American capitalism during the fall of the Soviet Union.

But its Golden Arches may be in the Kremlin's crosshairs as ties between Moscow and Washington have fallen to their lowest point since the end of the Cold War with consecutive rounds of U.S. sanctions over Russia's role in the Ukraine crisis.

"We have identified violations which put the product quality and safety of the entire McDonald's chain in doubt," Anna Popova, the watchdog's head and Russia's chief sanitary inspector, was quoted by Interfax news agency as saying.

The watchdog agency Rospotrebnadzor has previously been accused of acting in the political interests of the Kremlin, banning Georgian wine as Tbilisi strengthened ties with Washington and spirits from Moldova after the former Soviet republic boosted its drive to partner with the European Union.

A Moscow court told Reuters a regional branch of Rospotrebnadzor had asked it to declare production and sales of some McDonald's products illegal after the watchdog agency carried out inspections of McDonald's restaurants last June.

The regulator says the company is deceiving consumers about the energy value of its Cheeseburger Royales, Filet-o-Fish, Cheeseburgers and Chicken Burgers and about nutritional value of its milkshakes and ice creams.

Its also said in a statement that Caesar wrap sandwiches and a vegetable salad were contaminated with coliform bacteria, which indicates the likelihood of food poisoning.

McDonald's, which boasts of long lines at its restaurants across Moscow, some of which sit in view of the Kremlin's red walls, said it had not received any complaint from the regulator and had no information about the lawsuit.

"For the 25 years that McDonald's has been working in the Russian market, its main priority has been to provide quality and safe products to our visitors," the company said by email.

It added that its calculations of energy and nutritional value were based on the methodologies approved by state Russian institution.

The court will hold a preliminary hearing on Aug. 13 with the key hearing likely to be scheduled for September, the court's spokeswoman said.

McDonald's operates about 400 restaurants in Russia and sees the country as one of its top seven major markets outside the United States and Canada, according to its 2013 annual report.

The fast-food chain has often become subject to boycotts in various countries to oppose U.S. actions. In 2003, French boycotted McDonald's to protest against the war in Iraq.

In April, some Russian politicians called for all McDonald's outlets in the country to be shut after the company closed its restaurants in Crimea, whose annexation by Russia in March triggered U.S. and European sanctions.

(Writing by Thomas Grove and Maria Kiselyova, editing by David Evans)