Omid S, 27, an Afghan-born German national, and Huseyin O, also 27, a Turkish national, were taken into custody by federal police on Thursday, Sept. 18, in the Frankfurt area.
Both were accused of travelling to an IJU camp in the Afghan-Pakistan border area last year and taking supplies including binoculars, torches, and MP3 players to the remote camps.
A statement said they were associates of Adem Y, who was recently indicted for plotting car bomb attacks in Germany. Police arrested Yilmaz and two alleged co-conspirators last year before any attack occurred.
All the men were described as associates of the Islamist IJU, a shadowy Sunni Muslim group that is said to mimic the organization of al Qaeda a decade ago and which has been the main recent focus of German anti-terrorism inquiries.
A federal magistrate remanded the two arrested this week into custody on a charge of supporting a foreign terrorist organization and exporting arms of war.
Prosecutors said Pakistan security forces caught the Turkish national last year on his way to the camp and prevented him reaching it. Before his arrest, the other man, Y, had planned to visit the IJU camp this month.