TUNIS: A Tunisian man suspected of being involved with the Sept. 11 attack on a U.S. consulate in Libya has refused to be interviewed by FBI investigators, his lawyer said on Monday.

Ali Ani al-Harzi, jailed and under investigation in Tunisia over the attack having been deported from Turkey, said he would not see the Federal Bureau of Investigation (FBI) agents alone, Anouar Aouled told Reuters.

Harzi was one of two Tunisians named in October by the Daily Beast website as having been detained in Turkey over the attacks in Benghazi in which Christopher Stevens, the U.S. ambassador to Libya, and three other American officials were killed.

"I told Harzi only to accept the request if I am present with him," Aouled said. "But the Tunisian judge who is investigating the case told me the Americans want to question him alone. We refused."

An official at the Tunisian Ministry of Justice was not able to comment when contacted on Monday.

A U.S. government source said last month Harzi was not being investigated as a leader or organiser of the Benghazi attacks but rather as a possible participant.

The Daily Beast reported that shortly after the attacks began, Harzi posted an update on an unspecified social media site about the fighting.

It said Harzi was on his way to Syria when he was detained in Turkey at the behest of U.S. authorities, and that he was affiliated with a militant group in North Africa.