The National Hi-tech Crime Unit (NHTCU) has arrested six men and six women, with help from the National Crime Squad, the FBI and the US Secret Service.
Search warrants were used in Bermondsey, Edmonton, Shepherds Bush, Stoke Newington, Streatham, Tottenham and Ramsgate in Kent. Computers, passports, cheque books, bank cards, money and crack cocaine were seized.
In a statement, the NHTCU said the suspects were recruited by individuals close to Russian organised crime syndicates to open up bank accounts into which the stolen money was placed. It was then transferred minus a "commission", typically 7 percent, to Russia.
"Organised crime is targeting Internet users, and specifically Russian speakers, in the UK to launder money stolen from online bank accounts where people have been duped into handing over their account details," said Detective Superintendent Mick Deats, Deputy Head of the NHTCU.
Peats said that the gang has sent hundreds of thousands of pounds back to Russia.
"They have targeted a large number of high street and Internet banks, and because they are unable to break into the banks' systems themselves, they are resorting to duping account holders into parting with their details," he said.