BEIRUT Sunni Muslim insurgents have killed about 60 Shi'ite Muslims in a rebel-held eastern Syrian town where President Bashar al-Assad's agents had been trying to recruit and arm fighters for his cause, according to opposition sources on Wednesday.
The attack was another sign of how a revolt that began more than two years ago with peaceful protests against four decades of Assad family rule is descending into sectarian bloodshed.
A video posted online by rebels on Tuesday, entitled "The storming and cleansing of Hatla" showed dozens of gunmen carrying black Islamist flags celebrating and firing guns in the streets of a small town as smoke curled above several buildings.
"We have raised the banner 'There is no God but God' above the houses of the apostate rejectionists, the Shi'ites, and the holy warriors are celebrating," the voice of the cameraman says.
In the Damascus area, rebels reported that 27 of their comrades had been killed in an ambush near the town of al-Maraj.
Video uploaded by activists showed victims shot in the face or head. The camera scanned over several bloodied and dirt-coated corpses as men called out for help washing the bodies.
Musaab Abu Qutada, an opposition activist, said the men had been trying to break through a military blockade to bring supplies into rebel strongholds in suburbs of the capital.
Assad's forces, backed by the Lebanese Shi'ite group Hezbollah, won a significant victory by seizing the border town of Qusair last week and are now believed to be preparing offensives on rebel-held areas near Damascus and Aleppo.
Many of the fighters involved in the Hatla attack were said to be from the al Qaeda-linked Nusra Front. Hardline Sunni groups often refer to Shi'ites as rejectionists because they deny the legitimacy of the Prophet Mohammad's first successors.
"This is a Sunni area, it does not belong to other groups," one fighter shouted in the video purportedly filmed in the town of Hatla in the eastern province of Deir al-Zor.
The Syrian Observatory for Human Rights, a pro-opposition monitoring group that has reported abuses on both sides of the conflict, put the death toll in Tuesday's attack at 60, saying most victims were pro-Assad Shi'ite militiamen. Assad's minority Alawite sect is rooted in Shi'ite Islam. Most rebels are Sunnis.
The Observatory said many Shi'ite civilians, a minority in the mixed town of Hatla, had fled elsewhere in the province.
The conflict in Syria has stoked Sunni-Shi'ite tensions in the region, with Iran and Hezbollah supporting Assad, and Sunni-ruled nations such as Turkey, Saudi Arabia and Qatar backing the rebels. Sunni militants have also poured in to help the rebels.
Dozens of Kuwaitis gathered outside the Lebanese Embassy in Kuwait late on Tuesday to protest against Hezbollah's role in Syria. Protesters burned a picture of Hezbollah leader Hassan Nasrallah, a photo published in local media showed.
"The mujahideen in Lebanon are preparing ... for the battle which you started, Hezbollah," a Kuwaiti cleric named Shafi al-Ajami said in a video of the demonstration posted on YouTube.
"We are arming the mujahideen from here (Kuwait), and from the Arabian Peninsula, the Gulf states, Egypt, Jordan, Lebanon, Iraq and Turkey," he said.
He said funds for the effort were coming from "honorable people", not governments. Kuwaiti Islamists have started a Twitter campaign named "Kuwaitis prepare 12,000 mujahideen" as well as an online fundraising drive to help arm Syrian rebels.
Ajami said Syria would become "the graveyard for the party of Satan" - a common slur used by rebels against Hezbollah, whose name means "party of God" in Arabic.
In Hatla, some opposition activists said the attack included summary killings and the burning of Shi'ite places of worship.
Activist Karam Badran, who spoke to Reuters from Deir al-Zor, said only 20 people had been confirmed killed in Hatla but that another 20 had been taken hostage by the rebels.
He said the attackers' main motive was not sectarian, but what he and the Observatory said were government attempts to recruit militiamen of all faiths in an area rebels had held for a year. Shi'ites had not previously been harmed there, he said.
Badran said the Hatla killings had also followed an attack on Monday by pro-Assad militiamen on a rebel checkpoint outside the provincial capital Deir al-Zor, in which several opposition fighters had been killed and dozens wounded.
"Three of the men killed were three Shi'ite clerics. They were executed and hung on the gates of the town," Badran said. "But among the dead were also Sunnis (who had joined pro-Assad militia). This is really about betrayal."
(Additional reporting by Sylvia Westall in Kuwait; Editing by Alistair Lyon)