A senior Spanish prosecutor told the US Embassy in Madrid that Russia, Belarus and Chechnya had become virtual "mafia states", new disclosures of classified material by Wikileaks show.
A cable also questions whether Russian Prime Minister Vladimir Putin is implicated in the Russian mafia.
Another reveals that a powerful Ukrainian businessman told US officials he had ties to Russian organised crime.
The documents are among hundreds being released by the whistle-blower website.
On Wednesday the US online shopping giant Amazon reportedly blocked Wikileaks from its servers - a move welcomed by officials.
Access to Wikileaks' homepage was sporadic on Wednesday. The website had been using Amazon servers since its Swedish-based servers came under cyber-attack twice earlier this week.
The cables, published by the Guardian newspaper, show that in January 2010, Spanish prosecutor Jose "Pepe" Grinda Gonzales claimed that in Russia, Belarus and Chechnya "one cannot differentiate between the activities of the Government and OC (organised crime) groups".
A cable from the ...