Russia's EU ambassador has said ties would suffer if member states follow the US in putting sanctions on suspected Russian killers and fraudsters.

"It would poison relations, definitely," Vladimir Chizhov told EUobserver in an interview.

Chizhov (r): 'I have more confidence in the EU than I have in the US Congress' (Photo: consilium.europa.eu)

He added: "Well, I am sure that reason will prevail in the European Union. I have more confidence in the EU than I have in the US Congress."

The Congress' international committee in June approved the so-called Sergei Magnitsky Rule of Law Accountability Act.

If it becomes law, the US will impose visa bans and asset freezes on 60-or-so Russian officials suspected of conspiracy to murder Sergei Magnitsky - an auditor who exposed tax fraud in the Kremlin and who was found beaten to death in prison in 2009.

Chizhov said that he is "not threatening anybody."

But he noted that Russia might impose counter-sanctions on US officials if the Magnitsky bill gets through.

"The Russian Duma could launch a piece of legislation called the Guantanamo act or the Abu Ghraib act," he said, referring to US human rights violations in Cuba and Iraq.

EU foreign ministries do not want to confront Moscow for the sake of Magnitsky. But the case is attracting ever more political attention.

German Green MPs last week joined MEPs and MPs from Italy, the Netherlands, Poland, Sweden and the UK in calling for sanctions.

EU Council head Herman Van Rompuy and foreign affairs chief Catherine Ashton in April also urged Russia to hold a credible investigation.

Russia in the next few weeks is to say if a prison doctor is guilty of mis-diagnosing Magnitsky's medical condition.

But for Bill Browder, a British venture capitalist who employed Magnitsky at the time of his death, the doctor is being scapegoated to get senior people off the hook.

Browder has published evidence showing that one Kremlin tax chief, Olga Stepanova - among others - funnelled millions of euros of stolen money through accounts in Cyprus and Switzerland.

"Chizhov is a very articulate lobbyist for the rights of 60 Russian torturers and murders to travel and spend their ill-gotten gains in Europe. It is remarkable that he shows no concern for the nearly $800 million that was stolen from the Russian government," he said.

Chizhov told EUobserver that a second probe, by the Investigative Committee of the Russian Federation, is looking at potential Kremlin tax fraud.

When asked when it will submit its findings, he said it is too "complicated" to call.

When asked if Stepanova is under any kind of investigation, he said he would disclose the names of the officials being questioned.

His office later told EUobserver this will be "impossible," however.