TUNIS- Tunisia will not deport a suspected Islamist militant who once served as Osama bin Laden's bodyguard back to Germany because he is facing possible "terrorism" charges at home, a Tunisian judicial official said on Tuesday.

German authorities deported the man, identified only as Sami A., to his native Tunisia almost two weeks ago despite previous concerns that he might be tortured in his home country Tunisia and despite a court verdict allowing him to stay in Germany a day before the deportation.

Opposition politicians in Germany have criticized German Interior Minister Horst Seehofer for the handling of the case, while a German court has filed a motion to have Sami A. returned. 

Sofian Sliti, spokesman of Tunisia's anti-terrorist judiciary body, said the suspect would be tried at home if "terrorism" charges were confirmed during the investigation.

He is being held in a detention facility in Tunis.

"There is no way to deport him to any other country... There is no basis for this," Sliti told Reuters. "He will be tried according to the law on suspicion of terrorism outside the borders of the homeland."

Sliti identified the suspect as Sami Aidoudi.

Sliti rejected concerns he would face torture in Tunisia, which is the middle of a democratic transition after the toppling of autocrat Zine al-Abidine Ben Ali in 2011.

"We confirm that this will not happen. We confirm that the judiciary is independent and will not allow such practices. He is a citizen with full rights in a fair trial," he said.

Sami A. applied unsuccessfully for asylum in Germany in 2006. He was accused of undergoing military and ideological training in 2000 at an al Qaeda camp in Afghanistan and of being at different times a bodyguard for then al Qaeda leader bin Laden. He denied the allegations, but was arrested in Germany in June.

Seehofer, from the Bavarian sister party of Chancellor Angela Merkel's conservatives, takes a hard line on immigration and asylum issues and almost toppled the government earlier this month in a dispute over migrant policy.

Tunisia has won praise for its transition since 2011, agreeing on a constitution guaranteeing fundamental rights, holding fair elections and avoiding violence seen elsewhere in the region.

But human rights groups still sometimes accuse members of security agencies of abuses especially, against Islamist suspects, which are denied by authorities.

High unemployment has driven some 3,000 Tunisians abroad to join jihadist groups, many of whom have been killed in conflicts overseas, while returnees have been put under house arrest or jailed, according to officials.

(additional reporting by Madeline Chambers in Berlin, Writing by Ulf Laessing, Editing by William Maclean) ((mailto:Ulf.Laessing@thomsonreuters.com; Reuters Messaging: follow me on twitter @ulflaessing))