NEW YORK (CNN/Money) - Terrorists may be planning to attack financial institutions in the Northeast United States, the U.S. government said Friday, citing uncorroborated sources that could include members of the al Qaeda network.

The attack plans may include suicide bombers and involve al Qaeda operatives, anonymous government sources told CNNfn. The warning is based on information gathered in recent days from a variety of intelligence sources, including members of al Qaeda captured by U.S. forces in Afghanistan.

The FBI and top law enforcement officials stressed that the latest threat was unsubstantiated and said there were no plans to shut banks.

"It is important to note there is no specific threat being communicated to any specific institution," Attorney General John Ashcroft said in a speech in Pittsburgh. "We are not changing our assessment of the overall national threat level, and we are not asking banks to close or urging people to stay away from banks."

Attorney General John Ashcroft

"We are alerting law enforcement and financial institutions and the American people to be vigilant and to be aware of anything that appears suspicious," Ashcroft added.

Though the threat is unsubstantiated, and the FBI has no information about any specific plot or threats to any specific institution, it transmitted an alert to law enforcement officials and financial institutions in several northeastern states out of "an abundance of caution."

The FBI said the threat level for both the Northeast and the nation as a whole remains at "Yellow," or "Elevated," the third of five levels of risk according to the government's newly devised threat alert system.

And the FBI also said it has asked all law enforcement agencies and financial institutions to report any threats or suspicious activity to their local FBI office.

The Treasury Department said it had contacted the Federal Reserve, Federal Deposit Insurance Corp. and other regulators but had not discussed closing banks in light of the latest threat, and there was no word of any banks closing.

"We constantly assess any information we receive, work closely with law enforcement and will take appropriate precautions," Bank of America Corp. (BAC: up $1.00 to $71.62, Research, Estimates) said in a statement. "Unless the threat escalates, it is business as usual at Bank of America."

The FBI warned banks and law enforcement in Virginia, Maryland, Delaware, Pennsylvania, New York, New Jersey, Connecticut, Massachusetts, Rhode Island, Maine, Vermont, New Hampshire and the District of Columbia.

The decision to disseminate the threat information followed a meeting of the FBI, the Justice Department, the Office of Homeland Security, and the Treasury Department.

The news comes on the same day the U.S. Treasury Department added 10 more individuals and groups to its list of alleged terror financiers. Since the Sept. 11 terrorist attacks, the government and its partners overseas have frozen $104 million in assets belonging to entities alleged to support terrorism.

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U.S. stock prices were stable after the announcement, contrasting with the market reaction to the crash Thursday of a small airplane into an office building in Milan, Italy. Stock prices plunged and bond prices rose when that news broke; but when authorities said the crash most likely was an accident and not related to terrorism, calm returned to the markets.

Several banks in Washington, D.C., closed their offices Monday after a 13-year-old Dutch boy called authorities and said there was a plot to bomb a national bank in the city at noon that day.

The boy, who has not been charged with any crime, admitted he made the call as a prank. The FBI was skeptical of the call, but passed it on to financial institutions because of the specificity of some of the information the boy gave to authorities in his call.

The U.S. government believes al Qaeda is responsible for the Sept. 11 terror attacks and the bombings of the USS Cole and U.S. embassies in Kenya and Tanzania.