Updated

The Sept. 11 terrorist attacks could have been far worse, a new report says, with earlier plans calling for 10 hijacked planes hitting many more high-profile spots — including CIA and FBI headquarters, nuclear plants and West Coast skyscrapers in addition to the targets Al Qaeda actually struck in 2001.

But, the Sept. 11 commission's investigation found the terrorist network's notorious leader Usama bin Laden rejected that ambitious plan. Instead, he gave the thumbs-up on a scaled-back mission involving four planes hitting the World Trade Center in New York, the Pentagon in Washington, D.C., and the White House or the Capitol. Training for it began in 1999.

Raw Data: Read the Sept. 11 Commission's report (pdf)

The chilling new information was part of a 20-page report released Wednesday by the Sept. 11 commission, officially known as the National Commission on Terrorist Attacks Upon the United States (search).

The bipartisan group issued the findings as it embarked on two days of public hearings. Its final report is due out next month.

Sept. 11 plot mastermind Khalid Shaikh Mohammed (search) originally envisioned an attack involving 10 hijacked planes. Nine would be crashed into targets, but he himself would pilot the 10th, on which all adult male passengers aboard would be killed.

Mohammed would then land the plane and deliver an anti-American harangue upon landing, the commission reported.

Based on interviews with government officials and documents they reviewed, commissioners concluded that Mohammed initially proposed hitting CIA and FBI headquarters, unidentified nuclear plants and tall buildings in California and Washington state, in addition to the World Trade Center, Pentagon and White House or Capitol.

Mohammed, who is in U.S. custody at an undisclosed overseas location, told interrogators that rather than crashing his hijacked plane into a target, he wanted to land and make a political statement.

Mohammed proposed killing every male passenger aboard, landing at a U.S. airport and making a "speech denouncing U.S. policies in the Middle East before releasing all the women and children."

The report said Mohammed wanted more hijackers — up to 26, instead of the 19 who actually participated.

The commission also identified at least 10 Al Qaeda operatives who were to participate but could not take part for various reasons including visa problems and suspicion by officials at airports in the United States and overseas.

Far from a seamless operation, the report portrays a plot riven by internal dissent, including disagreement over whether to target the White House or the Capitol — a conflict that apparently never was resolved before the attacks.

Bin Laden also had to overcome opposition to attacking the United States from Mullah Omar (search), leader of the Taliban regime in Afghanistan, who was under pressure from Pakistan to keep Al Qaeda confined.

The pilot of the plane that crashed in Pennsylvania, Ziad Jarrah (search), nearly quit the plot, leading Mohammed to consider replacing him with Zacarias Moussaoui (search), who was taking flight training in Minnesota, according to the report.

Mohammed, however, has told his interrogators that Moussaoui actually was being considered for a second wave of attacks still in the early planning stages.

Moussaoui is awaiting trial on conspiracy charges. He's the only person charged in the United States in connection with the Sept. 11 plot.

Ultimately, Jarrah was persuaded to participate by Ramzi Binalshibh (search), who helped plan and finance the attacks from Germany. He also is in U.S. custody overseas.

Meanwhile, Fox News has learned that Abderraouf Jdey, one of seven terror suspects who were the subject of a major news conference with Attorney General John Ashcroft and FBI Director Robert Mueller last month, might have been a candidate to participate in the Sept. 11 attacks.

The commission reported that Jdey eventually withdrew his participation, though he was a possible candidate for another wave of attacks.

During the May 26 news conference about the seven suspects, the FBI reissued a "Be On the Lookout" alert for Jdey and others, saying they may be involved in or facilitating future attacks. Jdey's photo is on the FBI's Web site.

Among other new disclosures in the commission report:

— Mohamed Atta (search), the pilot of one of the planes that struck the World Trade Center and leader of the 19 hijackers, never met with Iraqi agents in Prague, Czech Republic. That purported meeting was cited as evidence of a possible Al Qaeda connection to Iraq. "We do not believe that such a meeting occurred," the report said.

— Mohdar Abdullah, an illegal immigrant living in San Diego, provided assistance to two of the hijackers and later made jailhouse claims that he had advance knowledge of the attacks. Abdullah last month was deported to Yemen.

— Bin Laden originally wanted the attacks to occur on May 12, 2001, seven months after the Al Qaeda attack on the USS Cole (search) in Yemen that killed 17 sailors. Later, bin Laden sought to have the attacks occur in June or July 2001 because Israeli Prime Minister Ariel Sharon (search) was scheduled to visit the White House. In both cases, Mohammed insisted the teams were not ready. Ultimately, Atta picked Sept. 11 because Congress would be in session.

— Bin Laden wanted the fourth plane to strike the White House, but Atta believed the White House was too difficult to hit. Eventually, Atta agreed to the White House but kept the Capitol in reserve. However, based on other exchanges between the hijackers, it remains unclear exactly which was the target on Sept 11.

— Atta said the hijackers planned to crash their planes to the ground if problems arose during the flights. Atta himself planned to crash his into the streets of New York if he couldn't strike the World Trade Center. The fourth plane crashed into a Pennsylvania field after passengers fought back against the hijackers.

— The plot cost upwards of $500,000. and no credible evidence has emerged that anyone in the United States provided financial support. There also is no evidence that Saudi Princess Haifa al Faisal (search), wife of that country's U.S. ambassador, Prince Bandar (search), provided any money to the conspiracy, directly or indirectly.

The Associated Press contributed to this report.