The Syrian opposition on Friday urged the Arab League to refer Syria to the United Nations Security Council after a mission by the pan-Arab body submitted a report on the deadly violence, dpa reported.
Syrian National Council (SNC) head Burhan Ghalioun arrived in Cairo for talks with Arab officials ahead of a meeting of Arab foreign ministers on Sunday to decide whether to extend the mission's mandate by another month.
"We are approaching a decisive juncture and, therefore, the efforts by the SNC to take our struggle to the Security Council require intensive efforts," the SNC said in a statement.
The opposition says the mission, whose mandate ended on Thursday, provided a cover for the government of President Bashar al-Assad to pursue a deadly crackdown on protesters.
Protests were held across Syria after Friday prayers. Security forces killed 15 civilians, mainly in the central city of Homs, a hotbed of anti-government demonstrations.
New York-based Human Rights Watch urged Arab League head Nabil al-Arabi in a letter to publish the mission's report and to seek an arms embargo and targeted sanctions against Syria at the UN Security Council.
"We urge you to publicly release the mission's final report in full to address concerns that the monitoring mission is being manipulated by the Syrian authorities," Human Rights Watch wrote.
Efforts by Western powers to push for a tough-worded resolution on Syria that includes a threat of sanctions are opposed by Damascus' allies Russia and China, which vetoed a similar resolution in October.
The Syrian army was preparing for an operation to retake the rebel-controlled town of Zabadani near the capital Damascus, a Syrian activist based in Lebanon told dpa. The military struck an unprecedented truce deal with rebels in Zabadani this week.
"We saw tanks taking positions near Zabadani," the activist said.
"This signals a new military operation, despite the ceasefire struck two days ago between the Syrian army and the defectors," he added.
Armed resistance has grown in recent months, with rebels staging increasingly sophisticated attacks against the Syrian army and more soldiers defecting to the rebel forces.
More than 5,000 people have been killed in Syria since anti-government protests erupted in March, according to the United Nations. Opposition activists says some 500 civilians have been killed by government forces since the Arab observers started their mission in mid-December.
The Syrian government has blamed the violence on armed gangs it says have killed more than 2,000 members of its security forces. It says Syria is the victim of a foreign conspiracy.