Arab League observers arrived in Damascus late Monday, as renewed violence claimed more lives in the central Syrian city of Homs.
A team of 60 monitors is visiting the troubled Middle East country to help oversee an agreement that calls for an end to the Syrian government's crackdown on dissidents involved with a nine-month-old uprising.
The latest violence in Homs, which is besieged by security forces, left at least 23 people dead on Monday, activists said. Several hundred civilians have been killed by government forces in just the last week, activists say.
Several media reports said the monitors would visit Damascus, Hama and Idlib on Tuesday. But some questioned whether they would be allowed full access.
"I very much doubt the Syrian regime will allow the observers to do their work," said prominent opposition figure Waleed al-Bunni from Cairo. "I expect them to try and hinder their movements by claiming that some areas are not safe, intimidating them or sending them to places other than the ones they should go to."
Officials with President Bashar Assad's regime say armed gangs are responsible for the latest violence. However, the British-based Syrian Observatory for Human Rights says most of the deaths reported Monday occurred as government forces shelled the neighbourhood of Baba Amr.
Activists said Monday's shelling using mortars and heavy machine-gun fire was the most intense since Friday.
The continuing violence has led to calls from foreign officials to allow the Arab League monitors to operate freely.
In a statement released late Monday afternoon, Foreign Affairs Minister John Baird described the violence as "disturbing" and called on Assad to step aside.
"We urge an immediate end to the regime’s violence and unfettered access for international observers so that the real reforms Syrians are demanding can finally begin," the statement said.
France, Syria's onetime colonial ruler, is also urging Assad's government to allow observers immediate access to Homs, which is the country's third-largest city.
The French government has been increasing diplomatic pressure on Assad to step down over the crackdown on anti-government protests, which the UN says has killed about 5,000 people.
It's not possible to independently verify casualty figures in Syria because the government bars international journalists from operating freely in the country.