The FBI is warning of possible further terrorist attacks within the next few days.
It says it has information to suggest they could be carried out in the US and on US interests abroad.
The targets are not specific, according to reports.
The FBI said in its warning: "Certain information, while not specific as to target, gives the government the reason to believe that there may be additional terrorist attacks within the United States and against US interests overseas over the next several days."
The FBI says it has ordered all law enforcement agencies to be on full alert.
It is also asking local police to be on the highest alert and for all Americans to be wary of suspicious activity.
Earlier this week US Attorney General John Ashcroft urged people to be alert and report any suspicious incidents.
He put most institutions on heightened security alert including sporting events, nuclear installations and chemical plants.
He says nuclear plants are on the highest possible state of security and border controls, major infrastructure, industry, events venues, water and powers plants and all law enforcement agencies were all on high alert.
Private companies were being asked to check their security plans and if necessary create or improve them.
This is an add-in to an earlier piece about the FBI saying there'll be more terrorist attacks.
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More than 300 kilos of explosives have gone missing in Texas. </b>
The material, used in seismic exploration, disappeared from northeast Harris County.
Officials say it is too early to know if the incident is terrorist-related.
AirJac Drilling Incorporated said the "shaped charges" were taken between Saturday and Tuesday.
"It could be very dangerous if they know what it is and how to use it," said Franceska Perot, a Bureau of Alcohol, Tobacco and Firearms spokeswoman.
Seismic charges, generally used for drilling and mining, usually come in different shapes and weights with a nonexplosive outer covering and explosive material inside.
An AirJac spokesman said the matter was being investigated, reports the Houston Chronicle.
"With everything going on now and with the heightened alert, we will be paying special attention to this," Ms Perot said.
Found this on the supanet website. Do any of you US have any more info on this?
Yo Norman - Kick up a STORM.
<A HREF="mailto:techie2000@supanet.com">techie2000@supanet.com</A>
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