A German court on Sunday issued an arrest warrant for Youssef Mohammed, a 21-year-old Lebanese student nabbed in Kiel by police in a swoop on Saturday. He stands accused of membership in a terrorist organization and of attempted murder.

Mohammed is suspected of planting one of two crude bombs in two abandoned suitcases that were discovered on July 31 on separate trains in the western German cities of Dortmund and Koblenz.

Police say they were set to go off 10 minutes before the trains arrived in the two cities. The explosives failed to detonate, but if they had, police say they would have killed a "high number" of people.

It has now emerged that Mohammed along with an accomplice, who are believed to be part of a wider Islamic network, had come close to exploding the two makeshift train bombs last month.

"The situation is very serious," German Interior Minister Wolfgang Schäuble said in an interview with German public television. "The danger has never been as high."

Broader terrorist network behind the attacks?

German Federal prosecutor Monika Harms said Youssef Mohammed's fingerprints and DNA matched that taken from one of two abandoned suitcases that were discovered on July 3.

The two men were captured on security cameras in the Cologne train station, dragging suitcases which contained the explosive devices onto the trains. Harms said the logistical sophistication of the plot suggested the suspect was part of a broader terrorist organization.

A massive manhunt is still on for the second suspect, suspected of planting the other device, whose identity has not yet been established, Harms said. The two men were not acting alone but within a "criminal organization with a solid structure," she added.

Citing sources close to the inquiry, Focus magazine said on its website that Mohammed was a Lebanese student who lived in Kiel. Local media reports said police were searching the suspect's residence, a student dormitory in the town. Quoting fellow students who lived near him, news magazine Spiegel said the Lebanese student was described as "friendly, polite, devout but relatively inconspicuous."

Link to Lebanon?

Investigators first thought that the devices were a blackmail attempt, but analysis of the contents revealed a possible link to Lebanon.

"We are now working on the basis that this was the work of a terrorist group based in Germany and that it was an attempt to kill a large number of people," Rainer Griesbaum, a federal prosecutor, told a press conference Friday.

The head of the Federal Crime Office, Joerg Ziercke, said the bombs were packed into identical black cases and consisted of gas canisters, alarm clocks, wires and batteries and soft drink bottles filled with a flammable liquid.

"The cases had been supposed to explode 10 minutes before the trains arrived at the stations," Ziercke said. He said a 100-strong team of investigators was still trying to establish why the devices failed to explode.

A note in the case found in Koblenz contained Arabic writing and a telephone number in Lebanon, and packets of starch with labels in Arabic and English were also found.

New generation of terrorists

The bomb plot has created jitters in Germany which has thus far been spared any major terrorist attacks since Sept. 11, 2001.

However, Interior Minister Wolfgang Schäuble has warned he could not rule out an attack on the German public transport system to rival the bombings in Madrid and London which killed dozens of passengers.

Schäuble has also warned in recent weeks that the conflict in the Middle East could inflame the Muslim community in Germany and lead to a radicalization among Arab youth. The minister said some 900 Hezbollah supporters as well 300 supporters of the Palestinian militant group Hamas were believed to be in Germany.

Politicians are also warning that the incident highlights the risk that a new generation of militants unknown to security services were ready to strike.

"That is the real reason for concern," Schäuble said. "We

don't know anymore who is living among us. Therefore we need to use every tool at our disposal."

Calls for tougher anti-terror measures

Schäuble said the government would have to seriously consider expanding video surveillance at airports and railway stations and implementing a long-discussed central anti-terrorism database that would allow various security agencies to access and exchange information and coordinate more closely.

Wolfgang Bosbach, deputy head of the conservatives in parliament, said he hoped the failed attack would be a "wake-up call" for those leery of tighter security.

"We need to introduce targeted modern video technology and

spot controls in specific danger zones," he said. "I think people will accept more surveillance because they don't just want to travel rapidly, but also safely."