Washington ? The FBI on Friday publicly warned more than 1,200 banks in the Northeast of possible terrorist attacks, and government officials said the unconfirmed information came in part from a high-ranking al-Qaida leader in U.S. custody.

Authorities cautioned that they had no information about a specific plot or threats to any financial institution, but a U.S. law enforcement source said authorities feared a suicide attack. Another senior official said the threat was not specified.

The warning of what the FBI described as possible “physical attacks” was based in part on information from Abu Zubaydah, the highest-ranking al-Qaida terrorist leader in U.S. custody, two officials said, but it was unclear if he was telling the truth.

Abu Zubaydah was one of Osama bin Laden’s top planners of terrorist operations, having knowledge of al-Qaida plots and operational cells. He was captured by Pakistani and U.S. authorities in Pakistan a few weeks ago and is recovering from gunshot wounds he received in the raid.

“We are not changing our national threat level. We are not asking the banks to close, nor urging people to stay away from banks,” Atty. Gen. John Ashcroft said.

He asked citizens to report suspicious activity to the FBI.

The threat information, based on interviews with captured al-Qaida suspects from Afghanistan, was given to the FBI, which, along with the Homeland Security Office at the White House, decided to remind financial institutions of a need to be vigilant.

Ashcroft said the information “may or may not be reliable.”

The government has issued industry-specific warnings since Sept. 11 about possible attacks against trucking companies, dams and water-supply systems, crop dusters and nuclear plants.

“Our policy is to share information with appropriate authorities and the American public when we have threat information that merits their attention,” Ashcroft said. “We believe that this information sharing disrupts and prevents terrorist activity.”

White House spokesman Ari Fleischer also defended the warning.

“These things are always judgment calls about providing the country with information … even if it’s not a lot of information,” he said.

The FBI warning went to more than 1,200 banks and savings institutions and to 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 FBI said the nation’s threat status remained at “yellow,” using the new system of color codes assigned by the Justice Department and Office of Homeland Security. The threat status for the Northeast similarly was unchanged at yellow, the FBI said. Yellow represents the midrange of threat status.

To qualify for the next-higher orange alert, the threats would have had to include a specific time and date and been corroborated and credible, one official said.

The warning came as authorities in Washington tightened security for three days of meetings of the International Monetary Fund and World Bank. The sessions, which run through Sunday, include finance ministers and central bank presidents from many nations.

The Federal Deposit Insurance Corp. said there were 613 FDIC-insured savings and loans in the Northeast and 650 FDIC-insured banks. The savings institutions in the region account for roughly one-third, or $433 billion, of the total $1.3 trillion in assets of all FDIC-insured S&Ls. Banks in the region have assets of $2.3 trillion out of $6.6 trillion held by all FDIC commercial banks.

FDIC’s definition of the Northeast region includes all the states in the FBI warning except for Virginia. The FDIC region also includes the Virgin Islands and Puerto Rico which were not part of the FBI warning.

The warning followed a bomb threat earlier in the week against an unspecified national bank in downtown Washington. Many bank branches shut down but there was no explosion. Police later said the threat was a prank by a 13-year-old Dutch boy.

Friday’s warning came on the seventh anniversary of the bombing of the Alfred P. Murrah federal building in Oklahoma City, and the ninth anniversary of the FBI raid on followers of cult-leader David Koresh in Waco, Texas.

The FBI announcement came a few hours after the Treasury Department blocked financial assets belonging to a Pakistan-based group and nine people believed to have provided financial support to al-Qaida, the terror network operated by bin Laden.