State prosecutors announced on Friday that the suspect, identified only as Adnan V. had been arrested on Thursday after searches in Offenbach and Frankfurt turned up a small amount of an explosive mixture and a homemade electronic device thought to be a potential detonator. Police also found evidence that the suspect had disseminated al-Qaeda propaganda on the internet and worked to recruit new members of the terrorist organization.

Federal prosecutors say the 24-year-old does not appear to be directly linked to recent al-Qaeda videos threatening Germans. Those videos, released in the run-up to last Sunday's national election, warned Germans that they would face terrorist attacks if they didn't vote to pull German troops out of Afghanistan.

Some of the videos have included images of potential targets, including Munich's Oktoberfest beer festival. This led authorities to ban air traffic over the annual event and to increase security at airports and train stations.

Heightened security ahead of October 3 celebrations

On Saturday, Germany celebrates German Unification Day and security has been heightened in Berlin. Authorities are anticipating around 500,000 people to descend up Brandenburg Gate in central Berlin for the festivities.

"Because of the changed security situation there will be significantly more security forces in place for October 3," Ehrhart Koerting, Berlin's senator for the interior, told Spiegel Online.

No cars or trucks will be allowed near the crowds and there will be bag inspections all around the area.

Although security forces are on high alert, officials maintain that there are currently no concrete threats against Germany.

hf/AFP/AP/Reuters
Editor: Andreas Illmer