NEW YORK (Reuters) - The Federal Reserve’s little-known role housing the assets of other central banks comes with a unique benefit to the United States: It serves as a source of foreign intelligence for Washington.

Senior officials from the U.S. Treasury and other government departments have turned to these otherwise confidential accounts several times a year to analyze the asset holdings of the central banks of Russia, China, Iraq, Turkey, Yemen, Libya and others, according to more than a dozen current and former senior Fed and Treasury officials.

The U.S. central bank keeps a tight lid on information contained in these accounts. But according to the officials interviewed by Reuters, U.S. authorities regularly use a “need to know” confidentiality exception in the Fed’s service contracts with foreign central banks.

The exception has allowed Treasury, State and Fed officials without regular access to glean information about the movement of funds in and out of the accounts, those people said. Such information has helped Washington monitor economic sanctions, fight terror financing and money laundering, or get a fuller picture of market hot spots around the world.

Some 250 foreign central banks and governments keep $3.3 trillion of their assets at the Federal Reserve Bank of New York, about half of the world’s official dollar reserves, using a service advertised in a 2015 slide presentation as “safe and confidential.”

The Bank for International Settlements, other major central banks and some commercial banks offer similar services, and clients usually have more than just one account. But only the Fed offers direct access to U.S. debt markets and to the world’s reserve currency, the dollar, making the U.S. central bank the top provider of this so-called custodial banking business.

In all, the people interviewed by Reuters identified seven instances in the last 15 years in which the accounts gave U.S. authorities insights into the actions of foreign counterparts or market movements, at times leading to a specific U.S. response. (Graphic: tmsnrt.rs/2tDxp7V)

In one relatively recent case, data from these foreign accounts offered U.S. authorities a sense of the mood in Moscow in March 2014, after Russia’s invasion of Crimea prompted the United States to respond with economic sanctions.

When foreign holdings at the New York Fed plunged about $115 billion, U.S. officials confirmed what others could only suspect, according to two former Fed officials: Russia’s central bank had pulled its funds.

While the Kremlin’s public response was defiant, Fed and Treasury officials concluded Moscow feared the United States would freeze Russia’s assets even though the account was not included in the narrow scope of the sanctions, according to one former official.

After about two weeks, Russia’s central bank returned most of the money to its Fed account, but the incident made officials monitor the account more closely for signs the sanctions had forced Moscow to draw down its reserves, the same source said. It was unclear what effect the sanctions had.

The Bank of Russia said it would not comment on “details of its operations and interaction with partners.” The Russian Embassy in Washington did not respond to an emailed query.

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NO PROMISE

The Fed acknowledged the practice of disclosing account intelligence, but declined to comment on individual clients.

“While our account agreement does provide for the sharing of information with the U.S. government in limited circumstances, we require a clearly demonstrated need for the information and a commitment that the information will be treated confidentially,” said a New York Fed spokeswoman. “This exception has been used on rare occasions and on a limited basis for such issues as compliance with sanctions requirements and anti-money laundering principles.”

The insights into the Fed operation come at a time when U.S. President Donald Trump threatens new economic sanctions on countries that could again be monitored through the foreign accounts. It also comes as U.S. intelligence-gathering has come under intense public scrutiny, with agencies investigating Russian meddling in last year’s election and possible collusion with Trump’s campaign. The Senate this month backed new sanctions on Russia in part to punish it for the meddling, while the Treasury added individuals and entities to those sanctioned over Moscow’s actions in Ukraine.

According to a draft account agreement the New York Fed published online last year, the Treasury or any other U.S. government agency or Fed bank must have “a need to know such information” to access it.

Seven people with direct knowledge of instances in which this exception was used told Reuters there was no working definition of the “need to know,” and that New York Fed lawyers would usually decide case by case.

The level of scrutiny by U.S. authorities and lack of clarity over what would constitute a “need to know” surprised some former foreign central bankers who spoke to Reuters.

The Bank of France, which also maintains foreign accounts, guarantees “full confidentiality” for its clients unless information is needed in a criminal investigation, said Christian Noyer, who was governor from 2003 to 2015. “It’s only in that case,” he said in an interview. “It’s not just to look at them and to know that.”

Less surprising was the fact that the United States leveraged the Fed’s position at the center of global finance, they said.

“The kinds of powerful central banks that can offer these services ... will want to use that power in ways that benefit their public remit,” Patrick Honohan, governor of the Central Bank of Ireland from 2009 to 2015, told Reuters.

Edwin Truman, who headed the Fed Board of Governors’ international finance division for more than two decades before joining the Treasury in 1998, said the Fed’s clients should not expect absolute secrecy.

“There is no promise to clients that the information in their accounts will not be shared with U.S. official circles,” Truman, now a fellow at the Peterson Institute for International Economics, said in an interview.

A Treasury spokesman said the department monitors transactions and collects data from all financial firms “both routinely and in the course of investigations (and) has the ability to request information from banks beyond the ‘need to know’ provision.” He declined to comment on interactions with the New York Fed.

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TREASURY CALLING

The U.S. officials interviewed by Reuters included executives and division heads, and people directly involved in discussions in which the confidentiality exception was used to analyze accounts that otherwise only a select group of Fed officials monitors. Most spoke on the condition of anonymity.

Day to day, a team of about a dozen New York Fed analysts oversees the accounts. This low-profile unit, called Central Bank and International Account Services (CBIAS), came under the spotlight last year when it transferred $81 million from the Bangladesh central bank’s account into the hands of hackers in one of the largest cyber heists ever.

The unit manages mostly Treasury and agency debt. It also oversees more than 500,000 gold bars that have accumulated in underground vaults since the New York Fed first opened accounts for Britain and France a century ago.

The requests for information became more frequent after the passage of the 2001 U.S. Patriot Act, mostly from the Office of Foreign Assets Control, a Treasury division enforcing sanctions and targeting terrorist financing, money laundering, and weapons and drugs trafficking. The Department can also subpoena confidential information.

Among the requests since then have been inquiries about the accounts belonging to Turkey, Iraq, Russia and others, often to help determine whether official funds were being used to finance sanctioned groups or individuals, according to three of the sources. A few countries of keen interest to the U.S. government have little or no funds at the New York Fed - such as Iran, which is sanctioned, and Saudi Arabia, which is not.

An official at Turkey’s central bank said “operations are routinely carried out according to a correspondent banking agreement with the New York Fed, which is the standard operational procedure in correspondent banking.”

Iraq’s central bank stands out among those subject to U.S. scrutiny because of the extent of cooperation between Baghdad and New York. Earlier this month, based on information and instructions from the Fed’s foreign accounts team, the Central Bank of Iraq blacklisted a money exchange firm suspected of ties with Islamic State and Al Qaeda. The Al-Kawthar money exchange firm, from the town of Qaim near the Syrian border, had its assets frozen in the action.

Fed officials rely on meetings and conference calls to advise the Iraqi central bank on how to track and freeze out local firms suspected of terrorist connections or of helping Iran bypass sanctions, an Iraq central bank official told Reuters.

“We have direct contact with the foreign assets monitoring office in the Fed,” the official said. In freezing the assets of Al-Kawthar, Iraq’s central bank followed Fed “verification procedures,” added the official, who declined to be named.

The U.S. Treasury announced the sanctions against Al-Kawthar on June 15, citing $2.5 million in money transfers it allegedly made to a firm linked to Islamic State facilitators. The owner of the money exchange firm was not available to comment.

Sometimes, a peek into the Fed accounts has provided the Treasury insight into market upheaval. At the height of the global financial crisis in 2008, Treasury officials asked the New York Fed whether one of its clients was behind plummeting demand for short-term debt of mortgage giants Fannie Mae and Freddie Mac, according to a former CBIAS official.

An analysis of the accounts showed that China’s central bank had curbed purchases, and that intelligence factored into the U.S. government’s decision to seize the agencies in September 2008, the person said.

The People’s Bank of China declined to comment.

In some cases, the Fed team handling the foreign accounts would activate the “need to know” clause if it spotted something unusual, two former Fed officials said.

Since the 2010 Arab Spring uprisings, for example, the New York Fed has made several inquiries with the State Department about Yemeni and Libyan assets, according to one of these officials.

The Fed team, which ranks accounts by levels of risk, sought clarity on whether the governments or insurgents were in control of those countries’ central banks, the official said.

A State Department official said it “maintains contact with counterparts in the Federal Reserve system to share information on political and security developments” so they can “better evaluate and understand foreign governmental structures, leadership, and financial risk.”

Representatives of Libya’s and Yemen’s central banks, as well as Yemen’s embassy in Washington, did not respond to requests for comment.