RENEE MONTAGNE, host:
This is MORNING EDITION from NPR News. I'm Renee Montagne. British authorities today arrested 21 people in the London area in connection with an alleged plot to blow up passenger aircraft flying between Britain and the United States.
British Home Secretary John Reid said authorities believe the plotters intended to use a liquid chemical substance to blow up a number of aircraft, and that Britain had raised its terrorist alert level to critical, meaning, as he put it, an attack is expected imminently.
And from Texas, where the president is vacationing, White House Spokesman Tony Snow said officials believe there was, quote, a direct threat to the United States. This morning the administration issued its highest terror alert level for flights between the United States and Britain, a red alert.
In Washington, Homeland Security Secretary Michael Chertoff said the plans were, quote, suggestive of an al-Qaida plot. Here's an extended excerpt of Secretary Chertoff's comments.
Mr. MICHAEL CHERTOFF (Secretary of Homeland Security): As I think you're all aware, British authorities have arrested 21 individuals who are now in custody who are alleged to have engaged in a plot to detonate liquid explosives on board multiple commercial aircraft departing from the United Kingdom and bound for the United States.
This plot appears to have been well planned and well advanced, with a significant number of operatives. The terrorists planned to carry the components of the bombs, including liquid explosive ingredients and detonating devices, disguised as beverages, electronic devices, or other common objects.
While this operation was centered in Great Britain, it was sophisticated, it had a lot of members, and it was international in scope. This operation is in some respects suggestive of an al-Qaida plot, but because the investigation is still underway, we cannot yet form a definitive conclusion. We're going to wait until all the facts are in.
We believe that the arrests in Britain have significantly disrupted this major threat, but we cannot assume that the threat has been completely thwarted, or that we have fully identified and neutralized every member of this terrorist network.
There is no current - currently no indication of any plotting within the United States. Nevertheless, as a precaution, the federal government is taking immediate steps to increase security measure with respect to aviation.
First of all, the United States government has raised the nation's threat level to our highest level of alert, severe or red, for commercial flights originating in the United Kingdom and bound for the United States. We've made this adjustment to coordinate our alert level with that that is currently in force in Britain. In Britain, as you've heard, they are now operating at their highest level, which is called critical.
Second, as a precaution against any members of the plot who may still be at large and recognizing the fact that we still have yet to take the investigation to its conclusion, we want to make sure that there are no remaining threats out there, and we also want to take steps to prevent any would-be copycats who may be inspired to similar conduct.
Accordingly, we are raising the threat level, or we have raised the threat level, with respect to aviation in general to high or orange. That will cover all inbound international flights other than flights from Great Britain, and it will cover all flights within the United States itself.
We're taking some additional specific steps. In light of the nature of the liquid explosive devices which were designed by the plotters, we are temporarily banning all liquids as carry-ons in aircraft cabins. That means no liquids or gels will be allowed in carry-on baggage. Any liquids or gels have to be checked as part of baggage to go into the hold.
MONTAGNE: That was Homeland Security Secretary Michael Chertoff speaking at a press conference this morning in Washington, D.C. Transcript provided by NPR, Copyright NPR.