An Arab League team is to take the 10-month-old crisis in Syria to the UN Security Council, as activists said almost 50 people were killed in unrest on Thursday, including 10 children.
UN human rights chief Navi Pillay said the United Nations could not keep track of the death toll in Syria's crackdown on dissent that has already cost more than 5,400 lives.
At the Cairo-based Arab League, the organisation's chief Nabil al-Arabi said he and Qatari Prime Minister Sheikh Hamad bin Jassim Al-Thani were to head to New York on Saturday to seek support for an Arab plan on Syria.
They are to "hold a meeting with the UN Security Council on Monday to seek ratification of the Arab League decision on Syria," for embattled President Bashar al-Assad to hand power to his deputy, Arabi said.
Arab League ministers on Sunday urged Assad to delegate powers to his vice president and clear the way for a national unity government within two months, a plan which Damascus has ruled out as interference in its internal affairs.
On Thursday, there was no let-up in violence on the ground.
"The toll for the day has risen to 34 civilians killed by the security forces in several regions of Syria, mostly in Homs," said the Britain-based Syrian Observatory for Human Rights.
Separately, seven deserters and eight regular soldiers died in clashes, according to the rights group, among them a colonel killed in Homs, a protest hub in central Syria.
The Observatory said the army launched an offensive on Thursday evening in the Karm al-Zeitoun district of Homs, killing 26 civilians, including nine children, and wounding dozens.
And in the rebel city of Hama, also in central Syria, where the army launched a major assault on Tuesday, four civilians were killed, including a 58-year-old woman shot dead by snipers, it said.
Elsewhere, one civilian reportedly died in the restive northwestern province of Idlib, and two others were killed in the suburbs of Damascus.
In the southern province of Daraa, cradle of the uprising, a teenager was killed when security forces fired indiscriminately on a student demonstration in the town of Nawa, the Observatory said.
Just north of Damascus, security forces attacked the town of Douma, another hotbed of anti-regime protests that activists say was in the hands of rebel troops last week before a withdrawal.
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"Violent clashes pitted security forces against groups of deserters at the Misraba bridge near the town of Douma, which was rocked by strong explosions," the Observatory said.
It said more than 200 arrests were made in the town during the assault, although there was no independent confirmation of the reports as foreign media are restricted in their coverage of Syria's unrest which erupted in mid-March.
On the diplomatic front, Pillay's admission of losing count of the dead came as European and Arab governments worked on a Security Council resolution condemning Assad's government for its deadly crackdown on dissent.
The authorities on Thursday organised loyalist rallies in a string of major cities as they reacted angrily to mounting criticism from Arab governments that have taken the lead role in diplomatic efforts to end the bloodshed.
Pillay gave a toll of more than 5,000 dead when she spoke to the Security Council in early December, but has not updated it.
Under secretary general B. Lynn Pascoe told the council on January 10 that at least 400 people had been killed since a widely criticised Arab observer mission deployed in Syria on December 26.
After meeting Security Council ambassadors again, Pillay said the toll had risen but added: "We are experiencing difficulties because of the fragmentation on the ground.
"Some areas are totally closed such as parts of Homs, so we are unable to update that figure," she told reporters.
Russia said on Wednesday it would consider "constructive proposals" to end the bloodshed but opposed the use of force or sanctions against its Syrian ally.
Foreign Minister Sergei Lavrov said any Security Council resolution backed by Moscow "must firmly record that it cannot be used or interpreted to justify anyone's outside military intervention in the Syria crisis."
Russia and China both blocked a previous Western attempt to have the Security Council formally condemn Assad's crackdown and impose stiff sanctions if he refuses to enter direct talks.
According to diplomats at the United Nations, European and Arab governments are drafting a new text they hope to put to a vote in the Security Council early next week.
In the capital, thousands took to the streets on Thursday in support of the government, chanting slogans hailing its longtime ally Moscow and denouncing the Arab League.