The Office of the Comptroller of the Currency, an independent branch within the Treasury Department, is examining JPMorgan's systems that are designed to monitor and filter such transactions, said the source, who is familiar with the situation.

The exact scope of the inquiry and the size of potential liabilities for the bank could not be learned.

JPMorgan spokesman Joseph Evangelisti declined to comment on Saturday.

In its quarterly filing with the U.S. Securities and Exchange Commission last month, JPMorgan said it expected heightened scrutiny by regulators of its compliance with new and existing regulations, including anti-money laundering laws.

The latest investigation comes in the midst of stepped-up efforts by regulators to crack down on money laundering, including transfers of drug money through bank networks and funds from countries facing international sanctions such as Iran.

The problem also has become a focus area for the Department of Justice, which wants to ramp up the number of criminal cases it brings under the Bank Secrecy Act, a law that requires financial institutions and their employees to take steps to prevent money laundering.

U.S. regulators also are potentially examining illicit transactions tied to Venezuela, the source said.

Earlier this summer, British bank HSBC Holdings Plc set aside $700 million to cover investigations that could result in one of the biggest ever settlements or fines. A U.S. Senate report criticized a "pervasively polluted" culture at the bank. The Senate panel examined transactions tied to Mexico, Iran, the Cayman Islands and Saudi Arabia.

Last month, New York's banking regulator reached a $340 million settlement with British bank Standard Chartered Plc after the regulator investigated transactions tied to Iran.

There have also been smaller cases in which the comptroller's office targeted weaknesses in how banks clear checks potentially tied to shadowy money transactions through a process called remote-deposit capture.

In April, the OCC identified a number of anti-money laundering deficiencies at Citigroup Inc. The inquiry investigated a monitoring gap at the bank tied to Citigroup's remote deposit capture business.

At the time, Citigroup said it had fixed the deficiencies or was in the process of doing so.

The New York Times earlier reported the news of the JPMorgan investigation.

(Additional reporting by Theopolis Waters in Chicago, Editing by Paritosh Bansal)

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