London, May 5 (IANS): A hacker has reportedly put 1.5 million stolen Facebook accounts up for sale on the black market, according to a media report Wednesday.

Researchers at Internet security firm VeriSign iDefense Labs said a hacker called 'kirllos' had put the login details on sale on Russian website Carder.su, thesun.co.uk reported.

Facebook has denied the reports saying 'kirllos' was known for making wild claims, the report said. Facebook spokesman Barry Schnitt said the company had tried to buy details from 'kirllos' during its own investigation but "the hacker was unable to produce anything for our buyer".

iDefense said the accounts had been offered at prices starting from $25 for 1,000 accounts for accounts with 10 or fewer friends, the report said.

Accounts with more than 10 friends were put on sale at the rate of $45 for 1,000 accounts.

The report quoted Rick Howard, director of iDefense, as saying that the case pointed to a boom in the illegal trading of social networking accounts from Eastern Europe to the US.