A former member of the independent commission that investigated the September 11 terror attacks has claimed that Saudi government officials supported the hijackers.

John F Lehman, who sat on the 9/11 Commission from 2003 to 2004, said there was an “awful lot of circumstantial evidence” implicating several employees in the Saudi Ministry of Islamic Affairs.

“There was an awful lot of participation by Saudi individuals in supporting the hijackers, and some of those people worked in the Saudi government,” he told the Guardian.

“Our report should never have been read as an exoneration of Saudi Arabia.”

Saudi Minister discusses 9/11 rumors

Alleged links between the country’s leadership and the world’s deadliest terror attacks have long been scrutinised, with 15 of the 18 hijackers being Saudi Arabian, along with al-Qaeda founder Osama bin Laden.

The 9/11 Commission’s 2004 report found no evidence of collusion between Riyadh and the terrorist group, concluding: “Saudi Arabia has long been considered the primary source of al-Qaeda funding but we have found no evidence that the Saudi government as an institution or senior Saudi officials individually funded the organisation.”

But controversy continues over an unreleased excerpt from a congressional inquiry on the issue, known as “the 28 pages”, which have remained classified.

Former President George W Bush claimed publication would damage America’s national security by revealing “sources and methods that would make it harder for us to win the War on Terror”, while the former chairman of the 9/11 Commission raised concerns that “raw, unvetted” material could damage innocent people.

In pictures: President Bush’s immediate response to 9/11 Show all 12 1 /12 In pictures: President Bush’s immediate response to 9/11 In pictures: President Bush’s immediate response to 9/11 11 September 2001 President Bush was visiting Emma E Brooker Elementary School in Sarasota, Florida as news of the attack on the World Trade Center broke In pictures: President Bush’s immediate response to 9/11 11 September 2001 The president and his staff, including Press Secretary Ari Fleischer (L) were then brought to a holding room at the school, where he prepared to address the nation In pictures: President Bush’s immediate response to 9/11 11 September 2001 President Bush was then rushed onto Air Force One and was flown to Barksdale Air Force Base in Louisiana. He watched television coverage of the attacks from his office on the plane In pictures: President Bush’s immediate response to 9/11 11 September 2001 President Bush talks on the telephone at the General Dougherty Conference Center at Barksdale Air Force Base In pictures: President Bush’s immediate response to 9/11 11 September 2001 President Bush is seen with his senior adviser Karl Rove at Barksdale Air Force Base In pictures: President Bush’s immediate response to 9/11 11 September 2001 The president with White House Chief of Staff Andrew Card at Barksdale Air Force Base. Before leaving the base, the president held a press conference at which he said, “Make no mistake: The United States will hunt down and punish those responsible for these cowardly acts” In pictures: President Bush’s immediate response to 9/11 11 September 2001 The president was consoled by Lt Col Cindy Wright of the White House Military Office aboard Air Force One. After leaving Louisiana, the president was flown to Offutt Air Force Base in Nebraska before he headed back to Washington In pictures: President Bush’s immediate response to 9/11 11 September 2001 President Bush arrived at the White House Presidential Emergency Operations Center around 7 pm. Here he is shown with his wife, First Lady Laura Bush, Vice President Cheney and National Security Adviser Condoleezza Rice In pictures: President Bush’s immediate response to 9/11 11 September 2001 At 8:30 pm, the president addressed the nation from the White House. In his speech, he set the tone for the wars to come in Afghanistan and Iraq In pictures: President Bush’s immediate response to 9/11 11 September 2001 “I’ve directed the full resources for our intelligence and law enforcement communities to find those responsible and bring them to justice,” the president said. “We will make no distinction between the terrorists who committed these acts and those who harbour them” In pictures: President Bush’s immediate response to 9/11 11 September 2001 The president’s speech on the teleprompter In pictures: President Bush’s immediate response to 9/11 11 September 2001 Immediately following the speech, the president had a national security meeting with Secretary of Defense Donald Rumsfeld, Vice President Dick Cheney, National Security Adviser Condoleezza Rice, White House Chief of Staff Andrew Card and others

But families of the 2,977 victims of the attacks have been demanding the documents’ release, with support from high-profile figures including the former mayor of New York, Rudi Giuliani.

Mr Lehman, an investment banker who served as Secretary of the Navy under Ronald Reagan, also called for the “28 pages” to be made public but said he did not believe that the Saudi royal family or the country’s senior leadership had any role in supporting al-Qaeda or the 9/11 plot.

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A report by the CIA inspector-general in June last year said there had been no reliable information confirming Saudi “involvement with and financial support for terrorism prior to 9/11” but added that agents believed “dissident sympathisers within the government may have aided al-Qaeda”.

The White House said the issue was not brought up during Barack Obama’s visit to Saudi Arabia last month.