Libya’s parliament chief announced on Sunday the arrests of some 50 people in connection with the killing of U.S. ambassador Chris Stevens in an attack on the American consulate in Benghazi last week, AFP reported.

“The number reached about 50,” Mohammed al-Megaryef, president of the Libyan National Congress, was quoted as having told CBS News.

Stevens and three other Americans were killed on Tuesday when suspected Islamic militants fired on the consulate in Benghazi with rocket-propelled grenades and set it ablaze.

Megaryef said “a few” of those who joined in the attack were foreigners who had entered Libya “from different directions, some of them definitely from Mali and Algeria.”

“The others are affiliates and maybe sympathizers,” he added.

Megaryef said the government has learned the attack was not the result of spontaneous anger over a U.S.-made anti-Islam movie which has triggered sometimes deadly protests across the Arab and Muslim world.

“It was planned, definitely, it was planned by foreigners, by people who entered the country a few months ago. And they were planning this criminal act since their arrival,” he was quoted as having told CBS.

Washington’s ambassador to the United Nations, Susan Rice, however offered a very different account, saying the assault began with a “spontaneous” protest over the video.

“Our current best assessment, based on the information that we have at present, is that, in fact, what this began as, it was a spontaneous — not a premeditated — response to what had transpired in Cairo,” Rice said.

“We believe that folks in Benghazi, a small number of people came to the consulate to replicate the sort of challenge that was posed in Cairo,” she told ABC’s “This Week”.

“And then as that unfolded, it seems to have been hijacked, let us say, by some individual clusters of extremists who came with heavier weapons. And it then evolved from there.”

Last week, however, U.S. sources told CNN they do not believe the attack in Benghazi was a reaction to the film but rather that it was “a clearly planned military-type attack.”

Al-Qaeda in the Arabian Peninsula (AQAP) has said in a statement the attack was revenge for the killing of the terror network’s deputy leader Sheikh Abu Yahya al-Libi in a drone strike in June.

AQAP on Saturday called for more violence against U.S. diplomatic missions in the Middle East and Africa, and urged attacks on American interests in the West, the SITE Intelligence Group said.

AQAP, Al-Qaeda’s Yemeni offshoot, did not claim direct responsibility for the deadly attack in Benghazi, but said the killing of Libi in a June drone strike in Pakistan “increased the enthusiasm and determination of the sons of (Libyan independence hero) Omar al-Mukhtar to take revenge upon those who attack our Prophet,” according to SITE.

Meanwhile, in interviews with Breitbart News and the Howie Carr radio show, Fox News military analyst Colonel David Hunt has laid the blame for the attack in Benghazi on Secretary of State Hillary Clinton and the State Department.

Colonel Hunt said that the American mission at Benghazi “was like a cardboard building, there wasn’t even bullet proof glass.” In addition, Hunt said the security guards inside the mission were private security guards who were not allowed to have bullets n their guns.