But Hezbollah's flagrant support for Assad's regime which stands accused by much of the international community of war crimes has angered many Arabs.
The presenter of a political show on Future TV, owned by Sunni Lebanese leader Saad Hariri, went on a 15-minute rant against Hezbollah this week, accusing its leader of "hypocrisy" in calling for the anti-film protests while remaining silent over Assad's deliberate destruction of mosques in Syria and killings of his Muslim countrymen.
Sheik Assir, speaking at the rally Friday, took a jibe at the Hezbollah protests without naming the group, saying it was shameful that posters of the "butcher" Assad were held up during Lebanese protests against the anti-Islam movie.
In remarks earlier this week, he accused Hezbollah "exploiting" the movie to recover some of the group's lost popularity and accused Nasrallah of trying to "snatch" leadership of the Islamic world.
"Why didn't Sheikh Nasrallah do anything when the prophets of freedom were martyred in Syria?" he asked.
Assir's rapid rise and growing following are symptoms of the deep frustration among Lebanon's Sunnis who resent the Hezbollah-led Shiite ascendancy in Lebanon.
The 44-year-old, bespectacled, skinny cleric with a long beard typical of hardline Sunnis was previously little known, a preacher at the Bilal Bin Rabah Mosque in Sidon. Now he is openly challenging and taunting Hezbollah like few have dared before, even taking aim at Nasrallah, a revered figure usually considered a red line in Lebanon.
Sunni bitterness still runs deep over clashes in May 2008, when Hezbollah gunmen swept through Sunni neighborhoods in Beirut after the pro-Western government of that time tried to dismantle the group's crucial telecommunications network. More than 80 people were killed in those clashes.
Moreover, a U.N.-backed special tribunal has accused four Hezbollah members in the 2005 assassination of former Prime Minister Rafik Hariri, Lebanon's most powerful Sunni leader. Hezbollah says the tribunal is a tool of Israel and the West.
Hezbollah still is Lebanon's single most influential player with considerable support among Shiites and unprecedented political clout. It holds a dominant role in Beirut's government and the prime minister is an ally, after the fall of the previous government sidelined Hezbollah's opponents, the U.S.- and Western-backed factions led by Hariri's son, Saad. As a result, its extensive arsenal of weapons and rockets is virtually untouchable for the moment.
Jihad Bahlo, a 23-year-old salesman in a Beirut clothing shop, said differences between Shiites and Sunnis are largely over politics, and that followers of the two sects often get on well on a personal level. A Sunni, he said his co-workers included Shiites and Christians, and no one discussed politics at work "because we are sick of it."
However, Sunnis tend to be fearful of Hezbollah's military might, said Bahlo, who is from a Sunni village in the predominantly Shiite Bekaa Valley.
AP correspondent Karin Laub contributed to this report from Beirut.
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