The White House on Wednesday warned that the foiled attack in Germany was proof of the danger terrorists pose, and pledged to continue to fight the threat.
"It's another reminder that terrorists are still out there and willing to do harm to innocent people" said Tony Fratto, a White House spokesman, after Germany said it foiled a potentially massive terrorist attack with the arrest of three Islamic extremists who were targeting airports, bars and discotheques used by Americans.
"And it's a reminder that we need to be vigilant in all of our efforts to find terrorists, deny them resources and hiding places, and prevent attacks. We appreciate the international effort, and the work of the German government in this case," Fratto added.
The men, two Germans and a Turk had amassed more than 700 kilogrammes of hydrogen peroxide, the same chemical used by suicide bombers in the 2005 attacks on London's transport system which killed 56 people, a German prosecutor said.
Fratto said President George W Bush "was briefed on the case yesterday and will continue to be kept up to date by his advisors."
One of the three had been arrested for spying on a US military base in December but was released soon afterwards, federal police chief Joerg Ziercke said.
All three of the men had attended a training camp in Pakistan in 2006.
There was no confirmation of media reports that the men had been targeting Frankfurt international airport and the giant US military base in Ramstein.