The U.S. Congress has released a report revealing that U.S. intelligence agencies received many tips about possible terrorist threats against the United States prior to the September 11 attacks on New York and Washington. The report was released Wednesday at the first public hearing of a joint Congressional committee probing intelligence lapses before last year's attacks.

A key Congressional staffer says intelligence agencies had far more reports of terrorist plots using planes as weapons before last year's hijacking attacks than U.S. officials have previously acknowledged.

But Eleanor Hill, staff director for the joint House and Senate Intelligence Committee, said agencies never looked closely at the potential threat of hijacked planes flying into buildings.

"From 1994 to as late as August 2001, the intelligence community had received information indicating that international terrorists had seriously considered the use of airplanes as a means of carrying out terrorist attacks," he said. "While this method of attack had clearly been discussed in terrorist circles, there apparently was little effort by intelligence community analysts to produce any strategic assessment of terrorists using aircraft as weapons."

Ms. Hill outlined multiple examples of intelligence information on the possible use by terrorists of airplanes as weapons. But she said none of the reports included any specific information on where, when or how an attack might occur.

Lawmakers were quick to express their concern.

Senator Richard Shelby of Alabama is the Senate Intelligence Committee's top Republican. "We now know that our inability to detect and prevent the September 11 attacks was an intelligence failure of unprecedented magnitude," he said.

Committee chairman Senator Bob Graham, a Florida Democrat, said the findings are meant to help the panel in its probe.

"These public hearings are part of our search for the truth, not to point fingers of blame, but with the goal of identifying and correcting whatever systemic problems may have prevented our government from detecting and disrupting al-Qaida's plot," he said.

But those comments brought little comfort to Stephen Push, whose wife was aboard the hijacked plane that crashed into the Pentagon on September 11.

"While I eagerly await the final report of your inquiry, one thing is already clear to me from the news reports about the intelligence failures that led to the attacks: If the intelligence community had been doing its job, my wife, Lisa Raines, would be alive today," he said.

The joint committee, which has held closed hearings into the September 11 attacks since June, has reviewed more than 400,000 pages of documents and conducted some 400 interviews.