FBI says 18 hijackers were on board planes

The FBI says 18 hijackers were on board the four planes involved in the US terrorist attacks.

The bureau's director Robert Mueller says two planes each had five hijackers on board and the remaining two passenger jets had four each.

Mr Mueller says all the hijackers were ticketed passengers.

US Attorney General John Ashcroft says the FBI tip-off hotline had so far received 2,055 phone calls.

He said: "Some of those leads have been helpful to the investigation. Our website has received more than 22,700 suggested tips. The FBI is working on thousands and thousands of leads."

Mr Ashcroft says none of the black-box flight recorders have been recovered.

He says retrieval of the black-box from the Pennsylvania crash site seems most feasible in the short term.