Moscow: Russia on Wednesday warned the United States that its decision to impose a visa ban on officials linked to the death in prison in 2009 of young lawyer Sergei Magnitsky risked harming a thaw in relations.

The State Department has announced it is banning visas for an unspecified number of individuals involved in the death of Magnitsky, which caused international anger and raised new questions about the Russian justice system.

"Attempts to interfere in an investigation and put pressure on the judicial authorities are unacceptable," the Russian Foreign Ministry said in a statement.

"It is clear that such actions can be a serious irritant in Russian-US relations and damage attempts to improve trust and constructive cooperation."

It slammed the US measures as "political games" and said that they had caused "indignation and concern in Moscow".

Magnitsky, 37, died in the Matrosskaya Tishina jail in Moscow of untreated pancreatitis after being held in pre-trial detention in a complex fraud case for 11 months.

The Washington Post reported on Tuesday that Moscow was threatening to curtail its cooperation on Iran, North Korea, Libya and the transit of supplies for Afghanistan over the issue but the statement did not give specifics.

"It goes without saying that such unfriendly measures will not go without response and the Russian side will take adequate measures to protect our country and the rights of Russian citizens," the Foreign Ministry said.

Russia-US relations have warmed under Presidents Barack Obama and Dmitry Medvedev, with Moscow offering support to the US hardline on Iran and refraining from using its veto on the UN resolution that allowed military action in Libya.

State Department Spokesperson Joanne Moore earlier confirmed Washington "has taken the appropriate measures so that individuals involved in the wrongful death of Sergei Magnitsky do not have US visas."

She did not say which officials were affected by the ban but added that the State Department "is required to deny visas to people involved in human rights violations, such as torture and extrajudicial killings."

The lawyer for Western investment fund Hermitage Capital had before his arrest accused top interior ministry officials of a scheme to fraudulently claim more than USD 200 million in returns on taxes.

(Agencies)