Russia said Tuesday it had paid millions of dollars for a tip-off that helped it find and kill Chechen rebel leader Aslan Maskhadov, as an outcry grew over Moscow's refusal to return his body for burial. Maskhadov was killed a week ago in a notable triumph for Russian forces, but Russian rights activists said the government has not treated its defeated foe with respect and criticized the decision to bury Maskhadov in an unmarked grave. The activists said the repeated display of the former Soviet army colonel's half-naked corpse on television risked further radicalizing the resistance. The Federal Security Service (FSB), successor to the Soviet-era KGB, said it had received a tip-off in response to a $10 million bounty on the leaders of the Chechen separatist movement. "This helped us establish the precise location of the international terrorist and band leader of the Chechen republic Aslan Maskhadov and conduct a special operation," an FSB spokesman said. He said the bounty had been paid out but would not say who had provided the tip-off. "They have received the money, but their identity will not be officially announced," the spokesman said. The rights activists said the decision to invoke Russia's anti-terrorism law and refuse to give Maskhadov's body to relatives for burial was a violation of human rights. "We think the refusal to hand back the killed man's body to his relatives for burial is shameful," said a statement by a group of prominent Russian activists published on the Web site www.zaprava.ru. "His death was not the result of an accidental clash, but, as the government has confirmed, the result of a well-prepared FSB operation. There is no doubt that the technical capabilities of the special forces would have allowed them to take him alive -- and he could have had a fair trial."