Zawahiri's latest video posted on a jihadist forum appeared to be around two months old as he offered greetings to Muslims for the start of the fasting month of Ramadan which ended on August 20.
Earlier this month Zawahiri's brother Mohamed gave an interview to CNN in which he outlined his personal 'peace plan' he said could lead to a rapprochement between Islamists and the West.
Speaking on the eve of the anniversary of the 9/11 terror attacks, Mohamed al-Zawahiri said he and his brother are ideologically inseparable.