Estonia's financial regulator said on Tuesday it would launch an investigation into Danske Bank's local branch after media reports said the lender had been aware of money laundering allegations at the unit as far back as 2013.

Danske had no immediate comment on the move by the Estonian regulator.

The Financial Supervisory Authority said in a statement it would look at whether Danske Bank knowingly withheld information from the regulator during a series of inspections it conducted at the bank's Estonian branch in 2014.

"We will immediately start a new investigation and we will be asking for the information that was not provided to us earlier," Livia Vosman, head of communications at Estonia's FSA, told Reuters.

The Estonian probe follows a report in Danish newspaper Berlingske and Britain's Guardian on Tuesday and a number of other international media outlets which said a whistleblower had alerted the bank in December 2013 about money laundering activities linked to Russia through its Estonian branch.

Responding to an earlier request by Reuters about the media reports, Danske chief executive Thomas Borgen said in an e-mailed statement: "We have launched a thorough investigation to get to the bottom of the events at that time in our Estonian branch. We are unable to comment the matter further until the investigation has finalised."