At least four people have died after security forces fired on protesters outside a mosque¹ in the Syrian city of Deraa, human rights activists³ say.

人权倡导者宣称，叙利亚保安部队在德拉城外面一座清真寺向抗议者开枪射击，造成至少四人死亡。

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The UN has said it is greatly concerned by the killings of protesters in Syria
Hundreds of people had earlier gathered in the streets outside the Omari mosque to prevent troops from storming it.

"They cut off electricity and the firing started," one activist² said.

The mosque has been the focus of anti-government demonstrations⁶ since Friday. At least 10 people have now been killed in clashes with police and soldiers.

UN Human Rights Commissioner⁸ Navi Pillay earlier urged the Syrian government to carry out a transparent⁹ investigation¹⁰ into the violence.

"We are greatly concerned by the recent killings of protesters in Syria and reiterate¹¹（重申） the need to put an immediate¹² halt to the excessive use of force against peaceful protesters, especially the use of live ammunition¹³（实弹） ."

"People have the legitimate¹⁴ right to express their grievances¹⁵（抱怨，不平） and demands to their government, and we urge the Syrian government to enter into a broad, meaningful dialogue with the protesters."

The EU has also strongly condemned¹⁶ the "unacceptable" crackdown.

The government has accused the protesters of being Israeli agents and infiltrators（渗透者） , and there have been arrests across the country.

On Tuesday, human rights activists said Louai Hussein, a former political prisoner who supported the protesters, was taken from his home in the Damascus suburb of Sahnaya.

However, reports say the governor of the Deraa region, Faisal Kalthoum, has been sacked - one of the demands of the demonstrators.

The authorities have also released the 15 children whose detention¹⁷ for writing pro-democracy graffiti prompted people to march from the Omari mosque after Friday prayers to demand greater political freedom.

The security forces later opened fire to disperse¹⁸（分散，传播） the demonstration⁷, killing⁵ four people. The following day, they fired on mourners at two of the victim's funerals, killing another person. An 11-year-old boy died on Monday after suffering the effects of tear-gas inhalation（吸入） .

Although the demonstrators have not demanded the resignation of President Assad, the unrest is the most serious challenge to his rule since he succeeded his father, Hafez, 11 years ago.

Syria has been ruled under emergency laws since 1963, and the Baath Party is known for brutally¹⁹ suppressing dissent²⁰.