-Había un peligro concreto e inminente de una acción terrorista
-3 miembros de AQ, todos marroquíes, algún informe los sitúa como relacionados con el atentado en Marruecos.
-La Cadena de televisión alemana ZDF dijo que los tres eran ciudadanos alemanes, uno de los cuales fue formado en el extranjero, y había sido arrestado antes de poder terminar de construir una bomba.
-Detenidos en Duesseldorf y Bochum
German police arrested three suspected members of al Qaeda on Friday, averting "a concrete and imminent danger" of a terrorist operation, authorities said.
The newspaper Bild quoted security sources as saying the three, all young Moroccans, were arrested in Duesseldorf and Bochum. It said police seized large amounts of explosives.
"We succeeded in preventing a concrete and imminent danger," Interior Minister Hans-Peter Friedrich said in a statement. "This proves that Germany continues to be in the crosshairs of international terrorists, and we need to remain vigilant."
Federal prosecutors and police had been investigating the three since April 15 over alleged membership of a terrorist organization and other charges.
European countries have grappled with militant threats for years, regularly arresting individuals or groups suspected of planning attacks some fear could mirror bombings in Madrid in 2004 and London in 2005 which killed more than 200 people.
Germany has been largely spared similar violence, although it has been the target of threats on Islamist websites and security officials have issued warnings that militant sleeper cells may be present in the country.
Berlin views its territory as a potential target because it has nearly 5,000 military personnel stationed in Afghanistan, the third largest contingent of the 150,000-strong international force fighting the Taliban-led insurgency.
Last November, the Interior Ministry tightened security at potential targets such as stations and airports after it said it learned of a plot, although the heightened alerts were later lifted.
Militants have also focused on Germany because of its role as host to the largest U.S. military bases in Europe.
In March, a gunman shot dead two U.S. airmen and wounded two others at Frankfurt airport, in an attack prosecutors said was probably motivated by anger over the war in Afghanistan.
The three men arrested on Friday were set to appear before an examining magistrate on Saturday, and a news conference was scheduled for 11 a.m. (0900 GMT) at the federal prosecutor's headquarters in Karlsruhe on the same day.
Bild said the arrests were made when police became suspicious after monitoring the suspects' mobile phones and computer.
It said the large quantity of explosives recovered included acetone, a volatile substance popular with militants since it can pass easily through detectors usually designed to locate nitrogen-based compounds.
German television station ZDF said the three were all German nationals, one of whom was trained abroad, and had been arrested before they could finish building a bomb.
Police did not confirm the Bild report that the suspects were Moroccans, or say whether the arrests were linked to an explosion at a busy cafe in the Moroccan city of Marrakesh on Thursday in which 15 people were killed.
(Additional reporting by Brian Rohan; editing by Andrew Dobbie)