(PTI): Russian hackers reportedly have stolen tens of millions of dollars from Citigroup, a claim rejected by the US banking giant.

Citing anonymous government officials, the Wall Street Journal reported that the hackers, related to a Russian cyber gang, attacked Citigroup’s computer systems extracting funds.

The bank though, strenuously denied the report, saying in a statement that Citigroup had no breach of its system and “there were no losses; no customer losses, no bank losses.”

The Journal says the attack on Citigroup’s Citibank subsidiary was discovered about four months ago.

It added that a committee comprising the FBI, Homeland Security Department and Citigroup have been investigating the case.