WASHINGTON, Nov. 5: Staff from the independent commission set up to investigate the Sept 11, 2001, attacks have secretly visited Afghanistan, Pakistan and Saudi Arabia, looking for clues about the origin of the plot.

The countries were among eight visited in recent weeks by commission officials in a series of trips not disclosed until this week.

Commission Staff Director Philip Zelikow said that he and two other staff members had interviewed scores of people, including officials from the countries and US government personnel serving there.

During their visit, which ended on Friday, Mr Zelikow said he and his colleagues visited Britain, Saudi Arabia, Yemen, Qatar, the United Arab Emirates, Pakistan and Afghanistan.

On a separate visit, other staff visited Canada, he added.

He said that the visit had been very successful and very useful in building a narrative of the run-up to the attacks, adding that they had learned much that was not currently public.

In Afghanistan the three met cabinet ministers and in Pakistan they met senior officials of the country’s intelligence service and diplomatic and law-enforcement officials.

In Afghanistan, an official of the Kabul government, speaking on condition of anonymity, said the team had met Defence Minister Gen Muhammad Fahim, Foreign Minister Abdullah Abdullah and President Hamid Karzai, among others.

The official said the clearest warnings had come from Ahmed Shah Masood, the military chief of the Northern Alliance. “During his visit to Europe in April 2001,” the official said, “Masood said very publicly that the United States was not paying enough attention to Afghanistan, and had no policy towards it.”

“He warned that the consequences could include terrorist attacks against the United States.”

Just two days before the Sept 11 attacks, Mr Masood was assassinated in a suicide bombing by two Al Qaeda terrorists posing as journalists with an explosive device in their camera.