Mohamed al-Magariaf, the head of Libya's General National Congress, said around 50 people were arrested, though another senior government official said the number was not that high.

The official said as many as 50 people have been brought in for questioning, but not all of them were arrested. They were people who were at a protest outside the consulate, but there was no indication yet that they took part in the violence, he said.

Those arrests were confirmed by Mustafa Abushagur, the prime minister of Libya, who added that other people may have been involved and the investigation is ongoing.

Two Tunisians were also detained for questioning in Turkey, and U.S. Secretary of Defense Leona Panetta said there was a connection between the arrests and the attack.

"We know there is some connection, but, frankly, we really don't have all the specifics," Panetta said.

The Tunisians, who had been on a watch list provided by the United States to Turkish authorities, were being questioned at the request of the United States, a U.S. official with knowledge of the investigation said.