AL-Qaeda said the deadly attack on the US consulate in Benghazi, Libya was in revenge for the killing of the network's number two Sheikh Abu Yahya al-Libi, SITE Intelligence Group reported.

"The killing of Sheikh Abu Yahya only increased the enthusiasm and determination of the sons of (Libyan independence hero) Omar al-Mokhtar to take revenge upon those who attack our Prophet," said al-Qaida in the Arabian Peninsula said in a statement, quoted by the US-based monitoring group.

Al-Qaida's Yemen-based offshoot did not claim direct responsibility for Tuesday's attack on the US consulate in Benghazi that killed the US ambassador to Libya, Christopher Stevens, and three other Americans.

But it stressed that "the uprising of our people in Libya, Egypt and Yemen against America and its embassies is a sign to notify the United States that its war is not directed against groups and organisations ... but against the Islamic nation that has rebelled against injustice."

The statement comes four days after al-Qaida chief Ayman al-Zawahiri issued a video eulogising Libi, his late deputy and propaganda chief who was killed in a drone strike in June.

Mohammed al-Megaryef, the head of Libya's national assembly, said today that the attack on the US consulate in Benghazi was planned and "meticulously executed."

Tuesday's attack by armed men in the eastern city of Benghazi came amid a wave of protests in the Muslim world against a US-made amateur Internet film deemed insulting to the Prophet Mohammed.

Suspected Islamic militants fired on the consulate with rocket-propelled grenades and set it ablaze on the anniversary of the September 11, 2001 terror attacks on the United States by al-Qaida.

Originally published as US consulate attack 'revenge' - Al-Qaida