Syria has not fully withdrawn troops and heavy weapons from towns, failing to send a “clear signal” about its commitment to peace, UN chief Ban Ki-moon said, underlining Western fears for the week-old truce.
In the first progress report since the Security Council passed a resolution on Saturday authorising the deployment of observers, Secretary-General Ban proposed an expanded mission of 300 personnel to monitor a shaky ceasefire between forces loyal to President Bashar al-Assad and opposition fighters.
After more than 10,000 people have been killed in 13 months of fighting, the report will be crucial in determining whether conditions are right for deploying the truce-monitoring mission at a Security Council meeting on Thursday, a day after an advance group of observers were surrounded by protesters against Assad's 12-year rule.
Chinese Foreign Ministry spokesman Liu Weimin said Beijing - which with Moscow has shielded Assad by blocking Security Council resolutions calling on him to cede power - was "seriously studying" the idea of sending observers to monitor the truce.
French President Nicolas Sarkozy said before a foreign minister's meeting on Syria in Paris that the solution for the crisis in Syria was the establishment of a humanitarian corridor that would allow the opposition to Assad to survive.
"Bashar al-Assad is lying ... He wants to wipe Homs off the map just like (former Libyan leader Muammar) Gaddafi wanted to destroy Benghazi," Sarkozy said ahead of the Friends of Syria meeting. "We called this meeting to gather all those who cannot stand that a dictator is killing his people."
"The solution is the establishment of humanitarian corridors so that an opposition can exist in Syria," Sarkozy told Europe 1 radio.
The scenes of UN vehicles being stuck in crowds and men running away to the sound of gunfire in the outskirts of the capital Damascus on Wednesday were an echo of an earlier monitoring mission by the Arab League, which collapsed in January.
"The Syrian government has yet to fully implement its initial obligations regarding the actions and deployments of its troops, or to return them to barracks," Ban told the Security Council in a letter obtained by Reuters on Wednesday.
"Violent incidents and reports of casualties have escalated again in recent days, with reports of shelling of civilian areas and abuses by government forces," he said. "The government reports violent actions by armed groups."
While the truce worked out with international envoy Kofi Annan has held in some parts of Syria, the army has kept up attacks on rebels in strong opposition areas such as Homs, Hama, Idlib and Deraa.
On Wednesday, 22 people were killed in Syria, including 13 civilians during shelling in Homs, said the British-based anti-Assad group Syrian Observatory for Human Rights. Syria's state news agency said 13 people were killed by "armed groups", including six law enforcement officials after a roadside bomb.
Syria pledged that it would cease using heavy weapons against what it calls foreign-backed terrorists, who have killed 2,600 soldiers and police. The ceasefire officially came into force last Thursday.
Damascus has challenged Ban over the size and scope of the monitoring mission, dismissing his efforts to increase the number of observers and secure European help in supplying planes and helicopters as unnecessary.
Syrian Foreign Minister Walid al-Moualem said on Wednesday 250 people was a "reasonable number", adding they should be from countries such as China, Russia, Brazil, India and South Africa - all more sympathetic to Damascus than the West or the Arab League. He also dismissed any need for UN aircraft.
In the report, Ban expressed some hope that there may be a chance for progress on ending the conflict.
He said the advance team had visited the town of Deraa and "enjoyed freedom of movement", but its initial request to visit Homs, a centre of the uprising against Assad, had been refused.
US Secretary of State Hillary Clinton, who will attend the meeting in Paris, said on Wednesday that Syria was at a turning point.
"Either we succeed with ... the Annan plan with the help of monitors ... or Assad will squander his last chance before additional measures have to be considered," she said.
Two previous Friends of Syria meetings, in Tunisia and Turkey, produced more rhetoric than results, and it was not clear what Thursday's smaller gathering in France might deliver.
Clinton, as she has in the past, appeared to leave the door open to other nations arming Syrian rebels, something the United States has itself rejected, though it is giving the opposition communications and logistical assistance.
Washington and its Western allies have shown no desire to intervene militarily or push for the sort of robust peace keeping force in Syria that might require 50,000 troops or more.
The Syria mission was negotiated by Kofi Annan, a former UN secretary-general now acting as an envoy of the United Nations and Arab League. Diplomats say Annan's main aim is to get a UN mission on the ground backed by Syria's supporters Russia and China, even if it is not big enough at first to do the job.