Monitors from the Arab League are due to arrive in Syria under an
initiative aimed at ending the violent crackdown on anti-government protests.
The UN says some 5,000 people have been killed in Syria since protests began in March
but right groups say the figure is much higher.Damascus blames the unrest on "armed gangs" seeking to destabilise Syria.
Russia is coming under pressure to speed up work on its draft UN resolution condemning the violence.
Moscow surprised diplomats by submitting the draft last week but there has been little progress since.
On Thursday, the US
issued fresh travel advice for Americans, urging "US citizens currently in
Syria
to depart immediately"."US citizens should not travel to Syria due to ongoing violence and civil unrest," the advisory said.
'Playing for time'
An advance party of about 30 Arab League observers, accompanied by members
of the media, will arrive in Syria
on Thursday to prepare for the arrival of the full delegation, which will have
a one-month mandate that can be extended by another month if both sides agree. Another group of observers is due in Syria on Sunday, and the mission is expected to be 150-strong when complete.
They will oversee Syria's compliance with the Arab League initiative, which calls for attacks to stop, troops to withdraw from the streets and detained protesters to be freed.
Damascus's decision to admit them was announced on Monday, after weeks of delays.
Syrian Foreign Minister Walid Muallem said they would be allowed freedom of movement and be protected by the government.
But critics of President Bashar al-Assad are sceptical about his decision, saying it is a ploy and he is simply playing along with the diplomatic process in an attempt to stave off more stringent UN action.
Radwan Ziadeh, a spokesman for Syria's main opposition coalition, the Syrian National Council (SNC), told the CA: "The Assad regime did not implement or accept the Arab League's initiative. It's true that they signed it but there is no action. It's only a signature on some papers."
"We gave them some of the hotspots in the different cities in Syria and we gave them instructions and we are in close coordination with the Arab League."
"But our position is that the Arab League is a very weak institution and they cannot actually protect the civilians. This is why we call [on] the Arab League to refer the case to the [United Nations] Security Council."
Activists point to an upsurge in attacks on anti-government protesters this week as evidence that Mr Assad is attempting to stifle unrest quickly.
The SNC, which is based outside Syria, says at least 250 people have been killed this week in north-western Idlib province.
Most of those killed in the Jabal al-Zawiya area, 40km (25 miles) south-west of the provincial capital Idlib, have reportedly been army defectors. Activists have also posted videos online said to show children injured in the fighting.
Journalists are not allowed to report freely in Syria so details are hard to verify.
But the London-based Syrian Observatory for Human Rights has accused government troops of carrying out an "organised massacre" in Idlib.
The SNC has called on the UN Security Council and the Arab League to declare a "protected zone" in the areas under attack by the army.
Critics say the regime is unlikely to be able to hold on to power if it complies with the Arab League plan and takes its soldiers off the streets, saying that would embolden anti-government protesters.
The US said promises from the Assad regime "have no credibility when they continue to be followed by outrageous and deplorable actions".
"The United States continues to believe that the only way to bring about the change that the Syrian people deserve is for Bashar al-Assad to leave power," said White House spokesman Jay Carney.
The CA's Jim Muir, who is monitoring events from neighbouring Lebanon, says the Syrian authorities may well be "clearing up unfinished business" ahead of the arrival of the monitors, with reports suggesting the security services are acting against army deserters and civilians trapped in a valley.
Damascus insists it is fighting armed terrorist gangs.
Russia under pressure
Our correspondent says opposition fighters may be trying to establish their
presence to gain a foothold for further expansion.Meanwhile, Western nations are pressing Russia to act faster on finalising its draft resolution on Syria.
Russia - along with China - vetoed a European resolution in October which threatened sanctions against Damascus if the killing continued. But last week, it submitted its own draft, which condemned both sides without mentioning sanctions.
Western nations said the proposal was not tough enough but that they were prepared to work on the document. There has been little progress since.
