Barclays is under investigation by UK watchdog Financial Conduct Authority for violating money laundering rules. ADRIAN DENNIS/AFP via Getty Images

Barclays is being investigated for potentially violating money-laundering rules, according to the Telegraph.

The news outlet reported on Thursday that Barclays confirmed that the Financial Conduct Authority, a financial watchdog in the United Kingdom, is looking into whether the bank's UK division had broken any laws by being too lax.

"The FCA's investigation focuses primarily on the historical oversight and management of certain customers with heightened risk," Barclays said, the Telegraph reported. "Barclays has been co-operating with the investigation."

The Telegraph said the FCA declined to comment about the investigation, which was revealed in the bank's annual report.

The Financial Times reported that the FCA requested an independent review of Barclays' systems last year after becoming concerned about a number of possible money-laundering incidents.

Barclays paid the FCA a $50 million fine last year after it failed to disclose its arrangement with Qatari investors during its financial bailout in 2008.

The FCA accused the bank of being "reckless" for not being transparent about the deal, the Telegraph said.

Barclays said it did not agree with the FCA but withdrew any action to "draw a line" under the controversy.