Official sources said Zuhair Mohamad Hassan Khalid al-Abassi, alias "Amjad Atta", was "arrested on June 1 under an international arrest warrant.
"A court imposed a travel ban pending a decision on whether he will be extradited," an official source told AFP, speaking on condition of anonymity.
A source in the security services said the 62-year-old suspect was freed on bail.
"He was released on bail pending the court's decision," the security source said, adding: "The case is still before the courts."
"Amjad Atta" is thought to have been the number three in the group's "special operations committee".