Regime forces fired on protesters at a protest hub near Damascus and killed at least 11 people around Syria on Thursday, even as peace monitors spread out across the country, activists said.
At least three demonstrators were killed and several others wounded in Douma, the protest centre just north of the capital, when security forces sprayed protesters with bullets outside a mosque, a rights group said.
The Syrian Observatory for Human Rights said the shooting broke out as a Arab League observers arrived at Douma's city hall, on the third day of a mission designed to halt a lethal government crackdown on dissent.
Following a two-day visit to Homs, which has seen the worst violence of the uprising, teams of observers were due to visit the neighbouring province of Hama, Idlib in the north and Deraa, where the protests started, on the southern border with Jordan.
All three provinces have seen hundreds of deaths of protesters and, more recently, of regime troops targeted by armed rebels.
Activists said they had little confidence that the mission would achieve its purpose of overseeing a peace deal supposedly agreed by Mr Assad two months ago.
Lt Gen Mohammed Ahmed Mustapha al-Dabi, head of the mission, sparked ridicule by describing the city of Homs, where it is thought more than 1,000 people have been killed, as being â€œnothing frightening", although he conceded â€œsome places looked a bit of a mess".
â€œYesterday was quiet and there were no clashes,â€? he said on Wednesday. â€œWe did not see tanks but we did see some armoured vehicles. But remember this was only the first day and it will need investigation.â€?
Observers in his mission were berated by residents who claimed they were being â€œslaughteredâ€? by regime attacks.
Bab al-Amr, an enclave of Homs in the hands of the rebels, had been subjected to a four-day attack by troops and tanks, some of it captured on video posted online, which lasted until Monday, the eve of the missionâ€™s visit to the city. Scores of people were killed When the monitors arrived, there was angry reaction to footage of one delegate appearing to turn away and light a cigarette as a man urged him to report the presence of snipers.
One monitor appeared to refuse to accompany a protester who wanted to show him the scene of a â€œslaughter", though another was seen on video being shown by a woman the bloodstains where her son had been shot.
Later, though, the monitors did visit a mosque where the body of a four-year-old boy, shot dead by regime troops after their arrival in the city, had been taken to await his funeral.
The opposition said that the mission was losing credibility. Radwan Ziadeh, a Syrian academic in exile and member of the Syrian National Council, said it did not have the â€œcapacity or experienceâ€? to stop what was going on.
â€œWhatâ€™s needed is international intervention,â€? he said. â€œWe need a buffer zone along the Turkish borders where the situation is still escalating.
Maybe the UN has to declare some â€™safe citiesâ€™.â€?
However, the Syrian Observatory of Human Rights said the mission was the "only ray of lightâ€? and was encouraging protesters to make their presence felt. â€œThe presence of the observers in Homs broke the barrier of fear,â€? a spokesman, Rami Abdel Rahman, said.
The deal the mission is overseeing is supposed to include the release of prisoners, the withdrawal of the army from the streets and negotiations with the opposition.
On Wednesday, the regime released 755 political prisoners it said did not have blood on their hands. But tens of thousands more remain in jail, and since none of the other terms have been met, many opposition leaders have called the missionâ€™s visit pointless at best and at worst a means for President Bashir al-Assad to play for time while continuing his military assault on rebellious districts.
Arab newspapers around the world have begun to highlight Lt Gen Dabiâ€™s controversial record as former head of intelligence for the Sudanese government, which is accused of genocide in Darfur during his term in office.
Activists estimate that around a third of the 5,000 protesters, civilians and opposition forces who have died in the uprising were killed in Homs.
France, which has become increasingly critical of the regime, issued an implicit criticism of Lt Gen Dabiâ€™s approach.
â€œThe brevity of their stay did not allow them to appreciate the reality of the prevailing situation yesterday in Homs,â€? a foreign ministry spokesman said. â€œThe Arab League monitors must be able to return quickly to this martyred city and be able to move freely and have all necessary contact with the population.â€?
Meanwhile, in Hama, another restive city which the mission was due to visit on Thursday, the army opened fire on protesters, killing at least six, according to local activists. Two died in Homs itself, the Syrian Observatory for Human Rights said