L'affaire Karachi is the most explosive corruption investigation in recent French history and the biggest scandal to personally threaten Sarkozy.
The potent saga of suspect submarine sales and illegal kickbacks centres around a bomb attack in Karachi in 2002, when 15 people, including 11 French engineers, were killed in what judges believe was a retaliation attack over unpaid government bribes.
The families of the French victims urged Sarkozy to testify to investigating magistrates about what he knows. "At the top of the French state there is a fear of this dossier advancing because it implicates Nicolas Sarkozy and those close to him," said Olivier Morice, the families' lawyer.
The Socialist party demanded "clarity" from the president and the immediate release of state classified documents to the investigation.