US on alert for truck attacks

Giant trucks transport chemicals around the US

Authorities in the United States have arrested nine more people on charges of illegally obtaining licences to transport hazardous materials.

Twenty-nine people have now been detained in an investigation into the possibility that the hijackers who attacked New York and Washington may have planned an attack using trucks loaded with hazardous substances, including chemicals and nuclear waste.

Truck companies and water and food suppliers have been put on high alert, while freeways now have official checkpoints, stopping big vehicles from entering densely populated areas.

Only days ago, the US grounded all crop-spraying planes for the same reason.

Shops in some areas have sold out of gas masks.

Investigation

So far, the Justice Department has not disclosed whether any of those arrested are linked to the attacks in New York and Washington.

Until we determine for sure what these people were up to, what their operation was and how they planned to go about it, I think it would be reasonable to be worried

FBI spokesman

But the authorities believe that some may have key information about other possible plans to target American cities.

The arrests follow warnings by the Federal Bureau of Investigation that trucks carrying chemical or biological agents could be used in attacks on densely populated areas.

The fear is that there may have been a plan to drive large amounts of deadly chemicals, nuclear waste or even biological agents into the heart of American cities, before releasing them - potentially killing tens of thousands.

Illegal licences

The warning comes after the discovery by the FBI that an official in Pennsylvania had issued a number of hazardous transportation licenses to people who were not eligible for them.

American shops are selling out of gas masks

Trucking companies have now been warned to look out for suspicious activity, particularly involving drivers hauling chemicals or radioactive waste.

Earlier this week, Attorney General John Ashcroft said one of the suspected hijackers, Mohammed Atta, had been gathering information on the use of crop-dusting aircraft, believed to be suitable for a biological attack, before the New York atrocity.

"Our investigation has uncovered several individuals, including individuals who may have links to the hijackers, who fraudulently have obtained or attempted to obtain hazardous material transportation licenses," he said.

Chicago driver

The inquiry started as a result of the arrest last week of Nabil al-Muraba, a taxi driver in Chicago.

He was holding a license to transport hazardous materials, and was wanted in Canada after trying to enter the US on a fake passport in June.

The authorities are also questioning Abdul Mohamman who is said to be a middleman, says the BBC's Richard Lister in Washington.

He says Mr Mohamman is thought to have taken some 20 people - many of them Arab American - to the Pennsylvania hazardous materials licence examiner, who issues the permits.