German officials say they have arrested three men on suspicion of planning a "massive" terrorist attack on U.S. facilities in the country. For VOA, Tom Rivers reports from London.

Unidentified man believed to be terror suspect, center, is led away in Karlsruhe, 05 Sep 2007

German authorities say the men are suspected Islamic militants and were arrested for allegedly planning bomb attacks targeting a number of locations including the U.S. Ramstein Air Base and Frankfurt's international airport.

German federal prosecutors say two of the three in custody are German citizens who converted to Islam. The men are believed to have received training at camps in Pakistan run by a group known as the Islamic Jihad Union. The third man being held is either Turkish or Pakistani and also allegedly received training in Pakistan.

German authorities says the men, all in their 20s, had obtained 700 kilograms of hydrogen peroxide which could have been used to produce explosive devices even larger than those used in the London and Madrid train bombings.

In Strasbourg, the European Union's top justice official, Franco Frattini, says despite the arrests, the threat level in Europe has not been reduced.

"All sources indicate that the threat of new terrorist attacks continues to be high," he said.  "Our member states' authorities have been able to prevent a number of attacks, for which we must be very grateful. I am talking about Spain, Italy, Belgium, U.K. and Germany."

Officials say the suspects were under surveillance for a long time. They were arrested Tuesday at a vacation home in central Germany.

In recent months, German and U.S. officials have warned of the possibility of new attacks, and security measures have been enhanced.