By Sebastian Usher
BBC World Media correspondent
A new audio tape purportedly from Osama Bin Laden has been broadcast as an exclusive on al-Jazeera, the Arab TV station that first made its name by showing al-Qaeda messages before and after 9/11.
Zawahiri's message has not been welcomed by the Arab media
It is the first new tape said to carry the voice of the al-Qaeda leader for just over a year.
During that time, two other figures have taken Osama Bin Laden's place as the leading voices of radical Islamic militancy.
They are al-Qaeda's number two, Ayman al-Zawahiri, and the Islamic militant leader in Iraq, Abu Musab al-Zarqawi.
Both have released communications this month and both have received short shrift in much of the Arab media, giving a sense that they may be losing ground in their propaganda struggle.
Their communications were also both broadcast on al-Jazeera, which remains the most watched Arab news station. Al-Jazeera broadcast Zawahiri's latest video as an exclusive on 6 January.
It ran several excerpts, though not the full video, and hosted a discussion programme on its importance.
The station also picked up the audiotape purportedly by Zarqawi from the radical Islamist website where it had been posted and broadcast excerpts on 9 January.
In the following days, a number of newspapers and commentators across the Arab world attacked and even ridiculed the two statements.
Their reaction shows that these two leading voices of violent, radical Islam may be finding it increasingly hard to get their messages across in the media battle they are waging for the hearts and minds of the Arab and Muslim public.
Several papers also highlighted what they see as a growing clash in the media between the radical Islamic voices espousing violence to achieve their aims and the more traditional Islamist organisations now using more peaceful, political means to reach their goals.
Although al-Jazeera led with the latest messages from Zawahiri and Zarqawi - just as they have done with the tape purportedly from Osama Bin Laden - a number of other Arab broadcasters did not broadcast the material at all.
TV stations in Iraq ignored them almost completely. The criticism directed by Zarqawi at Iraqi Sunnis who participated in the recent elections drew strong criticism from Sunni politicians.
Leaders of the main Sunni party, the Iraqi Islamic Party, issued denunciations of Zarqawi's call for Iraqi Sunnis to side with the insurgency and not the political process in the international Arab media, such as the Dubai-based TV station, al-Arabiya, and the influential pan-Arab newspaper, al-Hayat.
There was similar reaction from the Muslim Brotherhood in Egypt, which was attacked by Zawahiri in his latest video for taking part in Egypt's recent parliamentary elections.
The organisation's deputy leader, Muhammad Habib, warned on the Muslim Brotherhood website that Zawahiri's violent tactics would "open the doors to evil and create total chaos".
Zawahiri's statement was criticised in a number of other Arab media outlets, while Zarqawi's statement was mostly ignored.
One columnist, Nahid Hattar, in the Jordanian paper, al-Arab al-Yawm, portrayed the al-Qaeda number two as a parasite.
"American imperialism in Iraq is certainly on the verge of defeat," the columnist said.
Arab media have condemned the killing of civilians
"But the credit for that goes to the sacrifice of the Iraqi people... It will never go to al-Qaeda under the leadership of Osama bin Laden and Ayman al-Zawahiri, who appeared in his televised message to be thirsty, like a leech, for the blood of Iraqis, as well as haughty, stupid and lacking any connection to reality, just like George Bush junior."
The same criticism was levelled at Zawahiri by another columnist, Munir al-Khatib, in a Lebanese paper, Sada al-Balad.
"From inside a cave belonging to some unknown age, al-Zawahiri is using his stone-age language to brag about a battle, the price of which the sons of Iraq are paying," he said.
"It as if Saddam's evil deeds were not enough. The problem is that no-one is willing to argue with al-Qaeda's number two".
In Egypt, a commentary in al-Akhbar said that the "continued threats" by "al-Zawahiri and the other leaders of terrorism is in the end providing an acceptable justification" for the Americans to "occupy Iraq, Afghanistan and other places".
Little if any of this criticism is directed at what's widely seen in the Arab and Muslim world as a legitimate resistance movement in Iraq, but is instead aimed at al-Qaeda for trying to take credit for it.
Zawahiri has made no secret of the fact that al-Qaeda and the violent, radical groups inspired by it need to receive popular support in the Arab and Muslim world.
The growing distinction drawn in sections of the Arab media between what is seen as acceptable - some of the insurgency in Iraq, political moves by Islamist groups - and the unacceptable - Islamic militants' targeting of civilians - has been underlined by the coverage given to his latest statement and that of Zarqawi.
Al-Qaeda's propaganda war for the hearts and minds of the Arab masses is clearly facing increasing obstacles - from outright denunciation in the Arab media to studied indifference.
In the coming days, it will be interesting to see just how much weight and seriousness is given to the latest pronouncements allegedly made by Osama Bin Laden.