Several American government agencies did not act on intelligence inputs about terrorist activity that was received prior to the 9/11 attacks on the World Trade Centre and Pentagon, a congressional intelligence report has concluded.

The report, according to the ABCnews.com, says the government -- at least seven years before the attacks -- had information that terrorists were mulling over the use of aircraft as weapons.

A joint House-Senate committee has prepared the report.

The report says the information that terrorist might use planes to ram buildings 'did not stimulate any... collective US government reaction'.

In fact, the report says, those concerns were never even passed to federal transportation officials.

As early as 1998, according to the report, US agencies were getting a 'modest, but relatively steady, stream of intelligence' that Osama bin Laden's al Qaeda was planning an attack within the US.

"The (intelligence) community received information in 1998 about a bin Laden operation that would involve flying an explosive-laden aircraft into a US airport and, in summer 2001, about a plot to bomb a US embassy from an airplane or crash an airplane into it," ABCnews.com quoted the report as saying.

American officials, according to the report, concluded the 'greatest threat' was to US interests overseas.

Moreover, the report contends, some agencies failed to share intelligence information with others.

The report says Khalid Shaikh Mohammed -- believed to have masterminded the 9/11 attacks -- was in the United States as recently as May 2001. Though the CIA received information about the presence of Mohammed, the agency did not pass it on.

Similarly, the report adds, in early 2000, the CIA learned that Al-Midhar and Alhamzi had met with al Qaeda operatives in Malaysia. But that piece of information, according to the report, 'lay dormant' for more than 18 months.

The CIA also failed to warn US immigration officials to be on the lookout for Al-Midhar and Alhamzi, who later slipped into the United States unnoticed.

Had some of these 'dots been connected', the report concludes, the government would have 'greatly enhanced its chances of uncovering and preventing' the Sept 11 attacks.

Agencies