Russian Prime Minister Vladimir Putin has not lived up to his pledges to ensure power remained with the presidency when he left the office in May, US Defence Secretary Robert Gates said.
Gates said on ABC News television on Sunday that the United States had been hopeful that new the leadership would look more toward Russia's future, but developments "speak more of Putin having his hand on the steering wheel more than anybody else."
"There is a real concern that Russia has turned the corner and is headed back toward its past rather than its future," Gates said.
Putin left office in May after his handpicked successor, President Dmitry Medvedev, easily won the presidential election, the dpa reported.
Putin positioned himself to become the prime minister, raising questions about whether he would surrender power.
The United States criticized Putin during his tenure for cracking down on independent media and other important democratic institutions and mingling in the affairs of former Soviet states to re-assert Russia's Cold War-era sphere of influence.
Russia's August 7 invasion of southern neighbour Georgia has brought Russia's relations with the West to its worst crisis point since the end of the Cold War.
President George W Bush accused Russian of "bullying and intimidating" Georgia and other former Soviet states and has said Moscow's role in international diplomatic and economic institutions was at "risk."
Gates said the United States will re-evaluate the scope of its relationship with Russia in light of the military campaign in Georgia.
"We've been deeply disturbed by Russia's actions," Gates said, urging moderate Russian leaders like Medvedev to begin exercising more influence to "get the rhetoric under control."
Gates was referring to comments by a Russian general who threatened to target Poland and the Czech Republic for reaching agreements with the United States to host a missile-defence system.
General Anatoly Nogovitsyn, the deputy chief of Russia's general staff, said Russia's nuclear war doctrine calls for the targeting of anti-missile-defence systems.
"By putting up interceptors, Poland is placing itself at risk. In terms of priority, such targets are the first to be destroyed," he said.
Gates called the threat "empty rhetoric."
"Russia is not going to launch nuclear missiles at anybody," he said.
The United States and Poland initialled an agreement on Thursday that would allow the stationing of 10 interceptor missiles on Polish soil, after sealing a deal with the Czech Republic in July to host the system's radar.
The deployment is designed to counter the threat posed by Iran's growing ballistic missile capability, but Moscow views it as a threat to its strategic nuclear deterrent.
The United States maintains the system is far too small to disrupt an attack by Russia's hundreds of nuclear ballistic missiles and thousand of warheads.
The dispute had brought US-Russian relations to their lowest point since the end of the Cold War, relations that worsened during the last week after Moscow launched the massive military assault in Georgia in a conflict stemming from the Russian-backed separatist regions of South Ossetia and Abkhazia.