WASHINGTON - There was no single "smoking gun," but intelligence agencies missed opportunities to disrupt the September 11 plot in the months before the hijacked plane attacks, says a US congressional report released today.

If various pieces of information picked up by the FBI and CIA had been connected, it could have "greatly enhanced" the chances of uncovering and preventing Osama bin Laden's plan to attack the United States on September 11, 2001, the report said.

Senator Bob Graham, a Florida Democrat running for president who chaired the Senate Intelligence Committee during last year's inquiry, said the attacks "could have been prevented if the right combination of skill, cooperation, creativity and some good luck had been brought to the task."


House Intelligence Committee Chairman Porter Goss, a Florida Republican, said there was a lot of information still unknown about the plot in which four planes were hijacked and slammed into the World Trade Center, the Pentagon and a Pennsylvania field, killing about 3,000 people.

"This is an excellent snapshot, it's not a full anatomy," he said of the 900-page report from the joint inquiry of the House of Representatives and Senate intelligence committees conducted last year.

A section on whether there was any Saudi support for the hijackers remained classified except for one page.

Congressional sources said there was no conclusion that some people who came in contact with two of the hijackers in San Diego had acted on behalf of the Saudi government, but added that the issue needed to be aggressively investigated.

"Through its investigation, the Joint Inquiry developed information suggesting specific sources of foreign support for some of the September 11 hijackers while they were in the United States," the report said.

It also said US government officials had complained before the September 11 attacks that Saudi Arabia was uncooperative on issues relating to terrorism and bin Laden.

"A high-level US government officer cited greater Saudi cooperation when asked how the September 11 attacks might have been prevented," the report said.

"In May 2001, the US government became aware that an individual in Saudi Arabia was in contact with a senior al Qaeda operative and was most likely aware of an upcoming al Qaeda operation," the report said.

The September 11 attacks are a sensitive issue between Saudi Arabia and the United States because 15 of the 19 hijackers were Saudis.

"The idea that the Saudi government funded, organised or even knew about September 11th is malicious and blatantly false," Saudi ambassador Prince Bandar bin Sultan said. "Saudi Arabia has nothing to hide. We can deal with questions in public, but we cannot respond to blank pages."

The report details the contacts of a FBI informant with two of the September 11 hijackers, Khalid al-Mihdhar and Nawaf al-Hazmi, while they were living in San Diego, and more limited contact with a third hijacker, Hani Hanjour.

But the FBI agent who handled the informant said he had not been alerted to al-Mihdhar and al-Hazmi's significance. The report blamed the CIA for failing to put them on a watchlist despite having information that they were linked to al Qaeda and had visas to travel to the United States.

The FBI informant's contacts with the hijackers had been possibly the "best chance to unravel the September 11 plot," the report said.

At least five of the hijackers had contact with at least 14 people who had come to the attention of the FBI, including four who were the focus of active FBI investigations, it said.

An intelligence report in early summer 2001 said that Khalid Sheikh Mohammed, now believed to have been the mastermind of the attacks, was recruiting people to travel to the United States to plan "terrorist-related activity," the congressional report said.

Other intelligence reports from December 1998 until the attacks said followers of bin Laden were planning to strike US targets, hijack US planes, and two individuals had successfully evaded checkpoints in a dry run at a New York airport, the report said.

One report said that it was clear bin Laden was "building up a worldwide infrastructure which will allow him to launch multiple and simultaneous attacks with little or no warning."