The Foreign Ministry
The ministry condemned the "arbitrary punishment" of people who have not been proven guilty in court.
"Attempts to interfere in the investigation and to pressure the judiciary are absolutely unacceptable," it said in a statement on its web site.
The ministry promised that Moscow would retaliate.
"Clearly we won't let such hostile steps happen without a response and will take adequate measures to protect our country's sovereignty and our citizens from such wrongful actions by foreign states," it said.
The terse statement came a day after U.S. media reported that Washington had quietly issued entry bans on dozens of Russian officials accused by human rights activists of torturing and killing Magnitsky.
Magnitsky, a lawyer for Hermitage Capital, once the country's biggest foreign investment fund, died in a Moscow prison in November 2009. His supporters are campaigning among Western governments to impose sanctions against those responsible.
European governments have been hesitant to act on those demands, arguing that sanctions would jeopardize the Kremlin's efforts to investigate the case. Washington is the first to take any measures, casting a shadow on its much-touted reset of relations with Moscow.
The administration of President Barack Obama, in a commentary to U.S. senators that became fully public Wednesday, said current U.S. law "already bars admission … of aliens who have engaged in torture and extrajudicial killings."
"Secretary [Hillary] Clinton has taken steps to ban individuals associated with the wrongful death of Sergei Magnitsky from traveling to the United States," according to the document, which was published by a Washington-based blogger for Foreign Policy magazine, Josh Rogin.
That line of argument was angrily rejected as "absolutely cynical" by a senior United Russia official.
Andrei Klimov, deputy chairman of the State Duma's International Affairs Committee, told The Moscow Times that the United States was in violation of international agreements by punishing people who have not been convicted in court. "They ignore the principle of innocent until proven guilty," he said, adding that the decision "destroys the atmosphere of trust" that built up since Obama and President Dmitry Medvedev embarked on their reset policy.
Paradoxically, the move is actually an attempt to save the reset from greater damage looming in a Senate bill that envisages much wider and tougher sanctions.
The Sergei Magnitsky Rule of Law Accountability Act also includes asset freezes and would affect not only 60 law enforcement officers accused in the Magnitsky case, but also officials implicated in the killings of reporter Anna Politkovskaya and human rights worker Natalya Estemirova.
The Obama administration's written commentary addresses that bill, trying to convince senators to abandon it.
The memorandum stresses that there is no need for additional legislation after Clinton's decision.
It goes on to argue that "the threshold for naming names is ambiguous and would set a precedent for how the U.S. deals with human rights cases around the world," and that it imposes "quasi judicial requirements" on visa officers having to judge on applicants' eligibility.
It was unclear Wednesday whether senators would heed the arguments brought forward by the White House and the State Department.
But Democratic Senator Benjamin Cardin, the bill's main sponsor, seemed to backtrack significantly by suggesting in an interview with Foreign Policy magazine that the bill's future was up in the air.
"I'm working with the administration, working with the committee, and working with my fellow senators to determine how to proceed," he was quoted as saying.
"Two things can change strategy: One is what happens in Russia, one is what happens in the State Department. Both are fluid at this point," he said.
What makes Obama's position further uncomfortable is that U.S. lawmakers have in the past linked a repeal of the Jackson-Vanik amendment to the passage of Cardin's bill.
The White House has made lifting Jackson-Vanik, a Cold War-era set of trade sanctions, a policy priority because it would put the United States in violation of international law once Russia joins the World Trade Organization.
Obama has said he supports Moscow's goal to achieve WTO entry by the end of this year.
Observers doubt that the White House, currently locked in a dramatic standoff with Congress about how to raise the U.S. debt ceiling and avoid a default, has enough clout to move both Jackson-Vanik and Cardin's bill out of the way.
"The Magnitsky act's value as a bargaining chip may be minimal. Either way, it's clear that the Obama administration places great value on maintaining the gains of the reset and doesn't want anything to get in the way," Rogin wrote on his blog Wednesday.
Andrei Piontkovsky, a veteran political analyst and a visiting fellow at the Hudson Institute in Washington, warned that an escalation of the affair could also jeopardize the confirmation of Washington's next ambassador to Moscow.
White House sources said earlier this year that Michael McFaul, currently Obama's top Russia adviser, would become the new ambassador, but no official announcement has been made and the Senate has yet to set a date for his confirmation.
"If the reset is in tatters, why should the Senate confirm McFaul, who is the architect of the reset?" Piontkovsky said.