The 23-year-old student at the Fachhochschule in Frankfurt, who has been named only as Haddid N., was released to the Germans after Foreign Minister Guido Westerwelle raised his case with his US counterpart Hillary Clinton.
His sister Assma who works as a lawyer in Germany, said he would return to Germany as soon as possible. She confirmed he was in the German embassy in Kabul, and said the family was delighted by his release. “We have been able to speak with him on the phone several times,” she said.
The Süddeutsche Zeitung daily said earlier this week that the student from Frankfurt had been seized by US forces at his father's house in Kabul on January 8 and held at the Bagram air base in eastern Afghanistan.
The paper said that he had been detained at Frankfurt Airport in October 2009 while about to fly to Pakistan, on suspicion that he was going to a training camp for Islamic militants in neighbouring Afghanistan.
But prosecutors dropped their investigation last July and gave him his passport back. In November he flew to Dubai and instead of returning to Frankfurt, flew to Kabul in December, the report said.
The paper quoted his sister, saying that he was merely visiting his father, a businessman, in the Afghan capital.
But German police suspected otherwise and asked for the father's Kabul address - just a few days before his capture, the paper added.
German authorities deny having passed on any information to the Americans leading to the arrest, the paper said.
The Foreign Ministry said Saturday it was glad that a solution had been found and added that Westerwelle thanked Clinton for her aid. Its embassy in Kabul was ready to help the student to return to Germany as soon as possible, it said.