In Syria´s conflict, one side stridently argues that President Bashar al-Assad is under siege by agents of Gulf Arab states and the West. Opposition fighters, they say, are al Qaeda-allied terrorists and Israeli intelligence operatives. They characterize recent reports of Assad-regime massacres in the cities of Homs and Idlib as "a hysterical terrorist media campaign."

As the other side sees it, President Assad is "a monster." His regime, they say, is out to massacre the country´s Sunni majority.

These polar views define not only the Assad regime and those who oppose it: They are also the two starkly competing narratives being broadcast across the region by Arabic-language television news channels. These dueling accounts of Syria´s conflict are open proxies, observers say, for the political agendas of their backers.

"All you have is propaganda and counterpropaganda," says Marwan Kraidy, a professor at the University of Pennsylvania´s Annenberg School of Communication and an Arab media expert. "The number of channels is staggering, and the intensity of the sectarian hate and rhetoric is scary."

Satellite TV remains the most accessible medium for the Arab world´s masses. In areas where Internet penetration is sparse, news and views of the broader world come largely from the free stations picked up by dishes that are ubiquitous on rooftops from Baghdad´s slums to the remotest village in Morocco.

These stations broadly reinforce a regional narrative that pits Iran, which sees itself as the leader of the region´s Shiite Muslims and supports Mr. Assad, against Gulf Arab states led by Saudi Arabia, a center of Sunni Islam that is fully behind the opposition. The media battle is galvanizing populations across the region along sectarian lines and further fueling fears that a local conflict will metastasize into a regional one.

The region´s two main news channels—Al-Arabiya, which is based in Dubai and owned by Saudis, and al-Jazeera, which is owned and run out of Qatar—feature multisided discussions on Syria. But they can also often project the determination by oil-rich Sunni Gulf Arab states to cripple Iran and its Shiite allies, analysts say.

Several Salafi channels in tightly controlled Saudi Arabia have appeared to seize on Syria to escalate their case against Iran and Shiites in general, analysts add. Salafis are ultraconservative Sunnis whose interpretations of Islam overlap with those of al Qaeda.

"There will be slaughter and killing in every Arab country if the Syrian revolution is extinguished," said a news anchor this month on the Saudi-based Safa channel, adding that "Shiites are worse than Jews."

A caption on the screen read: "Sunnis are one blood."

Meanwhile, a range of channels friendly to the regime in Damascus— including Syrian state TV, Iranian broadcasters and Beiruit-based Al- Manar TV, owned by the Iranian-backed Lebanese militant group Hezbollah—have echoed Mr. Assad´s characterization that international coverage of Syria is a "media onslaught." They say they are battling an immense conspiracy waged by enemies in the Arab world, Israel and the West.

Anwar-2, an Iranian-funded channel that broadcasts to Iraq´s Shiite majority, regularly speaks about Saudi Arabia´s "extermination war against Shiites" and has called on Shiites in the region to mobilize against the Syrian opposition.

The media battle was evident as the Syrian government mounted 26 days of attacks against the Baba Amr neighborhood of Homs. Channels opposed to the Syrian regime—a group that is significantly larger, and deeper-pocketed, than the pro-Assadchannels—played up news the Syrian army was closing in for a final assault on Baba Amr. They reported massacres, rape, aerial bombardment and destruction of homes and mosques by the regime, not only in Homs but in several other Syrian hot spots.

Pro-Assad channels played down, or didn´t report, the siege and bombardment of Baba Amr. But once government soldiers took control of the neighborhood from opposition fighters, the same channels were let into the district before relief agencies to broadcast scenes of devastation and sing the Syrian army´s praises.

"This is what the Gulf-financed crows of death wrought," said an announcer on Syria´s Addounia, believed to be controlled by Mr. Assad´s maternal relatives, the Makhloufs. The channel ran nightly reports about massacres allegedly committed by opposition fighters, as well as bomb-making factories, arms depots and torture chambers said to belong to them.

Syria is all but closed to the Western press. Two Western journalists, who were among a knot of reporters who reported on what they characterized as a regime offensive that indiscriminately targeted civilians in Homs, were killed there in an attack that wounded several others.

As Sunni-backed channels convey agitation, fear-mongering and a "particular personal vendetta" against the Assad regime, the mirror- image narratives presented by the pro-Assad channels become all the more credible, said As´ad AbuKhalil, professor of political science at California State University, Stanislaus. For these channels, he said, "the lie doesn´t have to be good."

Syria´s Minister of Information Adnan Mahmoud said last week that state TV was covering events objectively and described recent successes in turning public opinion around.

An Al-Arabiya spokesman stressed his channel´s independence, saying perceptions that its coverage favors Syria´s opposition could be fueled by the fact that opposition members have made themselves more available than have regime figures. An al-Jazeera representative cited the Syrian regime´s boycott of the channel and restrictions on media operating in the field.

"There is not an editorial policy that chooses one side against another—the viewer is smart enough," said Mostefa Souag, managing director of al-Jazeera´s flagship Arabic news channel.

A Saudi TV journalist said that while mainstream Arabic news channels´ Syria coverage was sensational, it is no match to the pro- regime channels. But Salafi channels have nonetheless generated hatred that has in the end served the Syrian regime and its allies in Iran and Lebanon, by allowing them to rally their own constituencies in defense, according to Jamal al-Khashoggi, a Saudi journalist who is launching a TV channel this year funded by a member of what is seen as a moderate wing of the Saudi ruling family.

"They are part of the war of our Sunni fundamentalists with Shiite fundamentalists," he said of the Salafi stations. He added: "It doesn´t help our confrontation with Iran."

In several cases, the TV channels have become platforms for calls for action, which observers fear will fuel more violence in a region already rived by it. In addition to years of sectarian strife in Iraq, there have been episodes of sectarian clashes in Lebanon and most recently in Bahrain, where the Shiite majority is demonstrating against a Saudi-backed Sunni monarchy.

Earlier this month, Qatar-based Sunni cleric Yusuf al-Qaradawi issued a series of Syria-related fatwahs, or religious edicts, live on al- Jazeera, which has at least 35 million viewers across the world. He said jihad, or holy war, was mandatory there. "Elimination" of those collaborating with Mr. Assad´s crackdown on the opposition, including informants, was permissible, he said.

"When we engage in this rhetoric whereby the other side is only good when dead," said the University of Pennsylvania´s Mr. Kraidy, "we are setting the region up for a lot of trouble."

—Ali A. Nabhan contributed to this article. (Copyright © Dow Jones & Company, Inc.) 03/25/12)