Russian President Dmitry Medvedev says attempts to derail improvements in ties between Russia and the United States will fail.
Medvedev's remarks came in a letter to U.S. President Barack Obama amid a spy scandal.
Congratulating Obama on the U.S. July 4 Independence Day, Medvedev wrote: "[Our] constructive, neighborly relations...make it futile to try to downplay the importance of our achievements."
Washington and Moscow have said that the U.S. arrests last week of 10 alleged spies working for Russia will not damage ties.
The two sides have been working to repair strained ties, including trying to reach agreements on how to deal with Iran and North Korea's nuclear programs.