Four men have gone on trial in Germany for allegedly planning a series of deadly attacks on US targets in 2007.The three Germans and one Turkish national are said by prosecutors to have followed training in camps in Afghanistan where they learned how to make bombs. They were reportedly planning on using 10 times as much explosive material as was used in the 2005 London bombings. Their lawyer Johannes Pausch refused to say much about the case before the trial: “A trial like this one is difficult because of the sheer volume of documents and the time it will take. You have to be well prepared and focussed, but we will succeed,” he said. The men were allegedly caught after months of surveillance by police in the western Sauerland region. Officers seized enough material to make more than 500 kilos of bombs,its claimed. German police working together with the CIA helped foil the suspected plot in September 2007. Police say they appeared well-advanced in their preparations. Prosecutors allege they could have killed more than 50 people if they had suceeded. They say targets included nightclubs, pubs and the Ramstein US air base If convicted, the four men face up to 15 years in jail.