The police trade union's head, Konrad Freiberg, described the current situation as "very serious," and said Germans were not sensitive to the threats posed by terrorist groups.

"Everyone is talking about protective shields at banks and businesses," Freiberg told the daily Ruhr Nachrichten on Monday, Feb. 2. "We need a functioning protective shield from terrorism.

He added that the danger of terrorism in Germany exists but remains "absent from people's minds as long as nothing happens."

Since the Sept. 11, 2001, attacks in the United States, Germany's police force has shrunk by some 10,000 people, Freiberg said, adding that this meant Germany "was not able to monitor the risks -- a circle of between 60 and 100 people -- around the clock."

Freiberg said Germany, as the country contributing the third largest number of troops to the war in Afghanistan, was a logical target for terrorists.

Germany currently has 3,600 troops in Afghanistan as part of the International Security Assistance Force battling the Taliban in that country.

Electoral parallels to Spain

The Federal Criminal Police Office and the Office for the Protection of the Constitution sought on Sunday, Feb. 1, to highlight the possibility of attacks on Germany. The move comes after several videos were posted on the Internet in which masked men vowed in several languages to attack Germany for supporting the US-led military campaign in Afghanistan.

The threat comes in the lead up to elections in the Bundestag later this year, with some experts drawing parallels to the March 11, 2004, Madrid train bombings that occurred three days before Spain's general election.

In that incident, 10 bombs detonated on four packed commuter trains, killing 191 people and injuring around 1,800 more. Islamic militants were believed to be behind the attack.

Jose Luis Rodriguez Zapatero, leader of Spain's Socialist Party, which won the general election, immediately condemned the war in Iraq and said he would pull Spanish troops out of the country.

Exaggerated threat

But the head of the Essen Institute for Terrorism and Security Policy Research, Rolf Tophoven, warned against over-stating the possibility of a terrorist attack on Germany based on comparisons with the Madrid bombing.

"Germany in 2009 is not Spain in 2004," he told Cologne daily Kölner Stadt-Anzeiger. "In Spain, 90 percent of the population was against the Iraq troop deployment. And the socialist head of the government, Jose Luis Zapatero, would have withdrawn Spanish troops from Iraq without these attacks.

"In Germany, we have a clear parliamentary majority in favor of the armed forces deployment in Hindu Kush," Tophoven said. "In addition, a lengthening of Germany's Afghanistan mission was only decided on in October (last year), so the issue will not be raised in the Bundestag election."