Russia said Saturday it had put high-ranking US officials implicated in "human rights crimes" on a visa blacklist, warning Washington against increasing diplomatic pressure over the prison death of a lawyer.

Washington had earlier outraged Moscow by banning visas for an unspecified number of Russian officials linked to the 2009 death in prison of lawyer Sergei Magnitsky. His fate a symbol of abuses in the Russian judicial system.

Moscow's announcement of the visa black list -- and a threat to expand it -- was made during US Secretary of State Hillary Clinton's visit to ex-Soviet Central Asia. It comes as Russia's tough-talking Prime Minister Vladimir Putin is gearing up to reclaim the presidency in March elections.

Many fear his comeback will a deal a blow to the "reset" in relations championed by his protege, incumbent President Dmitry Medvedev, who has prided himself on building a rapport with US President Barack Obama.

The Russian foreign ministry released a statement Saturday saying it had made good on its earlier promise to put together its own list in response to Washington's "political provocation" against Russia.

"Relying on the principle of reciprocity, a list of US nationals whose stay in Russia is deemed undesirable has been put together," foreign ministry spokesman Alexander Lukashevich said.

He accused Washington of "moralising" and reeled off a number of alleged US rights violations such as "uninvestigated murders of civilians in Iraq and Afghanistan" and "indefinite detention of prisoners in Guantanamo".

The list "contains high-ranking Washington officials implicated in the aforementioned high-profile human rights crimes," Lukashevich said without providing any names.

The list also includes officials involved in "wrongful acts against Russian nationals in the United States," he said, noting they too would be denied entry to Russia.

The statement gave no further details, saying only the measure targeted the US officials who had authorised "abductions" of Russian nationals.

The statement warned that if Washington continued to put pressure on Moscow, the list would be expanded to include more US officials.

"A line has not been drawn -- if the US side continues on its path of visa confrontation we will be forced to expand that list," Lukashevich said.

Moscow released the foreign ministry statement as the top US diplomat was visiting the impoverished ex-Soviet nation of Tajikistan.

Russia had earlier said it was "bewildered" the State Department had decided to prejudge the guilt of its officials before Moscow had completed its own investigation.

Saturday's statement comes after Foreign Minister Sergei Lavrov admitted that Russia's judicial system could be improved. But Moscow did not need foreign advice, he added.

"We see our problems and will be dealing with them ourselves," he said in a live radio interview Friday night.

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

Analysts say US-Russia ties are likely to take a beating as Medvedev is gearing up to leave the Kremlin next year and Obama faces a tough re-election bid in 2012.

Earlier this week Putin went on national television, telling his foreign critics to "mind your own business" and fight inflation and "obesity" -- an obvious dig at the United States, where around 25 percent of people are obese, according to a recent Gallup poll.

In Germany meanwhile, news reports said authorities had arrested two suspected Russian spies who had allegedly been operating in the country for more than 20 years -- the first case of its kind since German reunification.

Der Spiegel said the man and woman, who lived as a couple, were arrested on Tuesday when police raided their home at Ballingen, between Stuttgart and Cologne in western Germany.

Both had denied the accusations against them.

Russia's SVR declined to comment on Der Spiegel's report.