KARLSRUHE, Germany - Three suspected al Qaeda members were working on making a shrapnel-laden bomb in Germany to attack a crowded place such as a bus -- a plot that shows Europe faces an ongoing terror threat, officials said Saturday.
Law enforcement officials said the trio, arrested Friday after being under surveillance for months, hadn't picked a specific target, but were experimenting with explosives and detonators before authorities swooped in.
The suspects include a Moroccan, a German with Moroccan citizenship, and a German with Iranian citizenship.
The attack was "still in the experimentation stage," anti-terrorism prosecutor Rainer Griesbaum said at a news conference. Officials decided to arrest the three in the western cities of Duesseldorf and Bochum after surveillance indicated they were tinkering with making a detonator and had explored possible explosive materials -- signs they might be close to carrying out an attack.
One member of the cell was overheard saying he wanted to "do a bus." The trio had been researching how to pack a bomb with metal objects that they could set off in a crowded area, officials said. They had also researched security measures at public buildings, train stations and airports.
The plot was described as part of the effort by al Qaeda's leadership in Afghanistan since 2010 to carry out an attack in Europe. Late last year, officials were warning of an attack in Europe, possibly modeled after the siege by militants from Pakistan in India's financial capital of Mumbai in November 2008 that killed 166 people.
The instigator of the German conspiracy was said to have received the assignment to carry out a bombing from a high-ranking al-Qaida member early last year.
The man described as the main suspect -- identified only as Abdeladim El-K., a 29-year-old Moroccan citizen -- left Germany in early 2010 and trained in an al Qaeda camp in Waziristan near the Afghan-Pakistan border, and returned last year to carry out the attack, Griesbaum said.
El-K. had at one time resided in Germany on a student visa but later returned illegally after abandoning his studies. Officials said they were not sure how he had re-entered Germany. He appeared before a judge and was charged with membership in a foreign terrorist organization.
The other two suspects, a 31-year-old with German and Moroccan citizenship and a 19-year-old with German and Iranian citizenship, were to appear in court later Saturday.
Officials said the trio had praised Thursday's deadly bomb attack on a cafe in Marrakesh, Morocco, although they had no known connection to that incident. Still, German officials feared they might take it as inspiration to strike.
Germany's top police official said despite successfully disrupting the plot, the nation remains a possible target of international terrorists.
"We cannot sound the all-clear," said Joerg Ziercke, president of the federal police.
Ziercke said the timing of the arrests was "a difficult security calculation," as authorities had to weigh the value of continuing to observe them against ensuring they did not succeed in carrying out an attack.
Material seized during searches Friday was being tested, but the suspects had discussed using acetone and hydrogen peroxide as bomb-making materials, Ziercke said.
Last year, France and Germany increased security after warning of a heightened threat of terrorist attack, and Germany said at least 70 of its citizens had gone to terrorist camps to prepare for attacks, and that some had returned to Germany. In October, the U.S. State Department advised American citizens living or travelling in Europe to be wary.
