"The decision of Swiss authorities to extradite Yevgeny Adamov to the United States directly involves Russia's legal interests," a ministry statement said.
The ministry also said Russia expected the Swiss high court to carefully and impartially consider all the legal aspects of the case. Adamov's defense team filed an appeal on the extradition Tuesday with the Federal Court in Lausanne, Switzerland's highest court whose rulings are final, attorney Stefan Wehrenberg said.
The ministry said Moscow had repeatedly disagreed with the decision of Swiss authorities to extradite the former Russian minister to the U.S. rather than to his home country, saying it contravened international law.
Until the Lausanne court hands down a decision on the appeal, Adamov will remain in custody in Bern. The court is not bound by a deadline.
Adamov, who served as Russia's nuclear power minister in 1998-2001, was arrested in Bern May 2 at the request of U.S. authorities, who accused the ex-minister of misappropriating $9 million granted to Russia for improving the safety of its nuclear facilities.
If convicted by an American court, Adamov may face a prison sentence of up to 60 years and a $1.75 million fine.
The Russian Prosecutor General's Office also launched proceedings against Adamov, charging him with embezzlement and abuse of office.
Both countries petitioned the Swiss judiciary for Adamov's extradition. The official extradition request by the U.S. was received by Swiss authorities June 24 and the request by Russia, May 17.
