In an interview with ABC News, Secretary of State of Condoleezza Rice expressed concern about Russia's increasing military assertiveness.
"I think the rapid growth in Russian military spending definitely bears watching," Rice said. "And frankly, some of the efforts — for instance, Bear flights in areas that we haven't seen for a while — are really not helpful to security."
Rice was referring to flights of Russian TU-95 "Bear" bombers, which Russia started this summer, bringing the Russian aircraft to the edge of American and NATO airspace off the coasts of Alaska, Britain and Guam.
In each case, the U.S. Air Force or NATO scrambled fighter jets to intercept the Russian aircraft, replaying a cat-and-mouse game that was common during the Cold War. But the Russian bombers had not made flights like these since 1992.
"We don't have an adversarial relationship with Russia any longer, and I would sincerely hope that Russian military activities, as well as Russian military expenditures, would reflect that," Rice said.
Russia's military spending has increased dramatically under President Putin. U.S. intelligence estimates that Russia now spends as much on its military as China, which has also raised alarms with its build-up.
"Russia is once again indisputably the number two military power in the world, second only to the United States," a senior U.S. official said.
Russia arms sales have also increased dramatically under Putin. And when it comes to arms, the list of Russian customers reads like a who's who of U.S. adversaries, including Iran, Syria, Venezuela and Burma.
Rice said she raised this issue directly in talks over the weekend with Russian leaders in Moscow.
"The Russians, of course, say that there's nothing illegal about these arms sales," Rice said. "I [told them] not everything that is legal in the narrowest sense is good for the international system.
"Clearly, in the case of Iran and Syria, you have states that are engaged in destabilizing behavior in one of the world's most volatile regions, and, by the way, a region where we and the Russians are working together to try to bring about peace between Israel and the Palestinians, a more stable Lebanon, a more stable Iraq. And so, yes, it's a problem."