Russian Prime Minister Vladimir Putin on Friday called the death of hedge fund Hermitage Capital lawyer Sergei Magnitsky in prison "a tragedy" but made no other comments.

"The fact that a person died while in prison is a tragedy. But I cannot make any comments here as I am not familiar with the details and do not know what claims were put forward against the man," Putin, on a visit to France, told journalists in Rambouillet.

Magnitsky, who was awaiting trial on tax evasion charges, died in a Moscow pretrial detention center earlier this month. The Russian Prosecutor General's office said that he died of a heart attack.

But Hermitage Capital head Bill Browder, who is also facing tax evasion charges in Russia, told the BBC earlier this week that Magnitsky was "denied medical attention" after refusing to sign a confession.

A top prison official admitted Thursday that the death of Magnitsky, 37, on November 16, was partly the fault of Russia's Federal Penitentiary Service.

Investigators said Wednesday that Magnitsky had conspired with Browder, who has reportedly been banned from entering Russia, to establish dummy firms to illegally buy and sell Russian energy giant Gazprom's stock.

RAMBOUILLET (France), November 27 (RIA Novosti)