A Syrian has been arrested in the south German city of Stuttgart on suspicion of helping to kidnap a UN peacekeeper in Damascus, prosecutors say.
The peacekeeper escaped in October 2013, eight months after being captured in Syria's capital.
Germany's federal prosecutors say al-Nusra Front, an Islamist group affiliated to al-Qaeda, was behind the kidnapping.
The man, 24, held in Stuttgart has been charged with war crimes.
Named only as Suliman A-S, he is suspected of having been a member of al-Nusra Front.
The peacekeeper, whose nationality was not named, had been based in the demilitarised zone on the Israeli-occupied Syrian Golan Heights and it is not known why he was in Damascus.
Who are al-Nusra Front?
Prosecutors say fighters demanded a ransom and Suliman A-S acted as the man's guard for two months.
They have not said why the Syrian is in Germany or whether he has been seeking asylum there.
Last year, 45 Fijian peacekeepers working for the UN in the Golan Heights were captured and then freed by al-Nusra Front fighters, who at one point demanded the group be removed from a UN list of designated terrorist organisations in return for the Fijians' release.