AFP - Four suspected Islamic militants went on trial Wednesday accused of plotting devastating attacks against US citizens in several German cities.
In what authorities call one of their biggest terror cases in decades, the three Germans and a Turkish national face charges of belonging to a terrorist group and conspiring to mount an explosives attack.
Security was extremely tight around the courthouse in the western city of Duesseldorf, with long lines at airport-style checkpoints.
The four defendants looked relaxed as they appeared before the five-judge panel behind bullet-proof glass, each wearing a beard.
"This will be a very big verdict, we will have a lot to write," presiding judge Ottmar Breidling said as the hearing began.
German media have called it the biggest terror trial since urban guerrillas of the Red Army Faction faced court in the 1970s. It could last two years or longer and the defendants could be sentenced to up to 15 years in prison.
The so-called Sauerland terror cell was named after a region east of here where authorities captured the suspects in September 2007 along with 26 detonators and 12 drums of hydrogen peroxide.
After months of surveillance, police using US and German intelligence said they caught three of the suspects red-handed, mixing chemicals to make the equivalent of 410 kilogrammes of explosives -- 100 times the amount used in the London transport bombings of 2005 that killed more than 50 people.
A fourth suspect was extradited from Turkey to Germany last November.
The suspects are accused of planning to car bomb US institutions in Germany and nightclubs popular with Americans.
Their aim, authorities say, was a deadly bombing "of unimaginable size", according to chief federal prosecutor Monika Harms, that along with targeting Americans would also punish Germany for its military presence in Afghanistan.
Authorities said the men planned bombings before October 12, 2007, when parliament was to vote to extend German participation in the NATO peacekeeping force in Afghanistan.
Prosecutors say the four are hardened members of the Islamic Jihad Union, an extremist group with roots in Uzbekistan and ties to Al-Qaeda which is believed to have set up militant training camps along the Pakistan-Afghanistan border.
Two of the suspects, Fritz Gelowicz and Daniel Schneider, are German converts to Islam, a third is a German citizen of Turkish origin, Attila Selek, 24, and the fourth a Turkish national, Adem Yilmaz, 30.
The cases of Gelowicz, 29, and Schneider, 23, have particularly shaken the country, raising questions how seemingly "normal" Germans could covert to a radical brand of Islam and plan attacks against their fellow citizens.
The prosecution has built its case around wiretapped conversations in which the cell discussed its plans.
In one, a suspect asks the amount of hydrogen peroxide solution required to kill an American: "How many grams do you need do blow him to bits?", according to media accounts citing evidence for the prosecution.
A man believed to be Schneider responds: "If you pack it in steel, 20 grams, 30 grams. Then he's dead."
A state secretary at the interior ministry, August Hanning, warned this week of a "wave of journeys" by Islamic extremists living in Germany to obtain training at overseas terror camps, underlining that Germany remained in jihadists' sights.
Germany, which opposed the 2003 US-led invasion of Iraq but has around 3,700 troops in Afghanistan under NATO command, has beefed up security and surveillance in response to the threat of militant attacks.
The closest authorities say it has come was in July 2006 when suitcases containing homemade bombs, placed on two regional trains at Cologne's main station, failed to detonate, averting an almost certain bloodbath.
The two would-be bombers have since been sentenced to long prison terms in Germany and Lebanon.
The September 11, 2001 attacks in the United States were also planned in part by an Al-Qaeda cell in the German port city of Hamburg.