Iraq: British 'fleeing' claims al-Qaeda
"Reports from Iraq point to the increasing power of the mujahadeen (holy warriors) and the deteriorating condition of the Americans," al-Zawahri said in video posted to the Internet on Sunday.
"And the decision of the British to flee is sufficient (proof of this)," he said.
The video, issued by al- Qaeda's media arm As-Sahab, was posted to Islamist websites the day that Basra became the last of four southern provinces once under British control to be returned to Iraq.
Britain now has 4,500 troops in Iraq, less than a tenth of the force dispatched by former prime minister Tony Blair to help topple Saddam in 2003.
In the 1 hour 37 minute video (photo), entitled 'interview with the Sheikh Ayman al-Zawahiri' and subtitled in English, he speaks to an off-camera interviewer, sitting beside shelves of books with his Kalashnikov rifle resting against the bookcase.
"Iraq is the most important of the fields (in which Islamic militants are fighting)," al-Zawahiri says. He dismisses optimistic remarks made by current US officials concerning progress in battling the insurgency.
"Jihad in Iraq is going excellently at present. Contrary to the claims of America's giant propaganda machine, which seeks to hoodwink people, I have learned that the mujahadeen are growing in number. Security is getting worse for the Americans - just look at Britain's decision to flee," he adds.
The video includes footage from insurgent videos and TV news broadcasts, including a segment showing critical remarks about the US strategy in Iraq by Ricardo Sanchez, former top US commander there.
Al-Zawahiri defends the al-Qaeda linked group Islamic State in Iraq, but distances himself from the crimes against civilians committed by some of its members.
"There exist among the ranks, hypocrites and traitors who commit these crimes," who seek to encourage Sunni groups to ally themselves with US led forces against al-Qaeda.
"The mujahadeen must swiftly expose these individuals, to defeat the plots of the Americans," he states, calling on other insurgent groups to unite with the Islamic state in Iraq.
The video also contains images of Pope Benedict XVI which last several seconds, showing his recent meeting with Saudi Arabia's King Abdullah in Rome.
"I ask how appropriate it was for him [Abudullah] to visit the pontiff, who has offended Islam and Muslims?" al-Zawahiri states.
Al-Zawahiri also criticises Islamic scholars, especially Saudi ones, who forbid Muslims from waging Jihad against the US, describing them as "those muftis who follow the Bush school."
He highlights the importance of the Internet to Jihad, claiming it has broken down 'information monopolies' such as that of the BBC "when jihadists are waging their most dangerous battles against the Crusader-Zionist enemy."
Islamist websites carrying the video have invited sympathisers to send in questions in the next month for al-Zawahiri to answer in an 'open interview'.