A Lebanese student suspected of a failed attempt to blow up a German train had contacts in Hamburg, authorities said Tuesday, drawing attention back to the northern port city where three of the Sept. 11 homicide pilots prepared for their attacks on the U.S.

Nearly five years since the attacks on New York and Washington, the case has provided shocking proof for many that Germany is now also a terrorist target.

The main suspect, identified by authorities as 21-year-old Youssef Mohamad el Hajdib, was arrested Saturday in Kiel, about 30 miles north of Hamburg, on suspicion of placing one of two suitcase bombs in German trains on July 31.

On Tuesday, federal prosecutors said they had identified the second main suspect, while police searched his Cologne apartment as well as addresses in Kiel and Oberhausen.

CountryWatch: Germany

ZDF television showed police leading away one man in handcuffs after one of the raids, and said a second had also been detained.

However, prosecutors said the second suspected bomber, whose name they did not release, remains at large.

The Sueddeutsche Zeitung newspaper, citing unidentified investigators, said the fugitive was also a Lebanese national and was believed to have fled Germany.

It also said the men were suspected of having contact with the radical Islamic movement Hizb-ut-Tahrir.

Neither prosecutors nor federal police would provide more details.

Though the bombs failed to explode, the fact that terrorists had planned an attack here was a wake-up call for any Germans who thought the country's vehement opposition to the Iraq war would somehow insulate it from becoming a target.

The failed plot immediately rekindled a debate over whether enough was being done domestically to combat terrorists and prompted calls for wider video surveillance and an anti-terrorism database.

While there have been other terrorism plots uncovered since Sept. 11, none has come so close to success.

"I have always said we are threatened by terrorism, and the threat has never been so near," Interior Minister Wolfgang Schaeuble told ZDF television after el Hajdib's arrest, calling the case "unusually serious."

Authorities are now investigating ties between the suspect and the Muslim community in Hamburg, the city where Sept. 11 suicide pilots Mohamed Atta, Marwan al-Shehhi and Ziad Jarrah all lived undetected before moving to the United States to attend flight schools, said Manfred Murck, deputy head of the Hamburg state agency that tracks extremism.

"It seems like we do, once again, have some contacts to Hamburg, which is not really surprising," he said. "If somebody lives in Kiel and feels involved in the Islamist scene, it seems to be more or less plausible that he may have a friend or a mosque to visit in Hamburg."

Murck would not elaborate on specifics about the suspect's connections in Hamburg, saying only that "we are working, of course, to find out what in our files can help us to identify possible contact persons."

German authorities were widely criticized for not picking up on the Sept. 11 plot, and stiffened counterterrorism laws in the wake of the attacks, though with police-state excesses of the country's Nazi past in mind, were wary of going too far.

Now, with train station video footage helping track down el Hajdib and concerns about the safety of the railroads, Deutsche Bahn has already said it will step up its own security measures. Schaeuble has also said he is drawing up proposals to stiffen counterterrorism laws, and Chancellor Angela Merkel on Monday underlined the importance of video surveillance while calling for the acceleration of a proposal to establish a database on terror suspects to help investigators.

Politicians and civil rights groups have responded with warnings against eroding people's privacy.

But where Germany before Sept. 11 was seen as a relatively comfortable base for terrorists to live and operate — but not a target — that is no longer the case, said Kai Hirschmann, deputy director of Essen's Institute for Terrorism Research and Security Policy.

"This has changed dramatically, because intelligence agencies and police are now very much trying to arrest them ... and the scene is under constant surveillance," Hirschmann said.

Germany is also seen as being on the side of the U.S. and Britain, despite its opposition to the Iraq war, for helping train Iraqi police and military outside the country, taking a large role in operations in Afghanistan, and making other contributions to the so-called "war on terror," he said.

"We are all said to be part of the so-called 'crusader alliance,' and that, step by step, has brought us to the focus as well and it doesn't help at all that we didn't take part in the Iraq war," Hirschmann said.

In the case of the failed train bombings, the evidence points to poorly trained radicals not closely linked to terrorist networks, Hirschmann said.

The bombs were cobbled together from propane barbecue canisters to be triggered with gasoline and makeshift detonators that went off but failed to ignite the gas. They were found in suitcases on regional trains in Dortmund and Koblenz.

"It looked rather rushed or amateur. There might be some connection with the Islamist network, the jihad network, but not in the sense that we witnessed in Madrid or London," Hirschmann said, referring to the train bombings in Madrid and the London subway bombings.

He said el Hajdib was more likely to have received encouragement, rather than logistical support, from Hamburg's radical Islamic community.