Syrian opposition chief Abdelbaset Sayda urges defections
The newly appointed head of the opposition Syrian National Council (SNC) has called on government officials in Damascus to defect.
Speaking in Istanbul, Abdelbaset Sayda reiterated the group's rejection of foreign intervention, unless it was sanctioned by the United Nations.
Meanwhile, violence has intensified in the province of Homs, with reports of blasts and machine-gun fire on Monday.
At least 35 people were killed there in bombardments on Sunday, activists said.
The BBC's Paul Danahar, who is in the city of Homs, says mortar rounds are being fired into the old part of town every couple of minutes. He says large black plume of smoke can be seen rising above the area.
The UK-based Syrian Observatory for Human Rights has also reported violence elsewhere in Syria, including:
- the central rebel-held town of Rastan, where it says helicopters have strafed rebel fighter positions
- Qusair, in Homs, where it says rebels attacked and killed an unspecified number of Syrian troops
- villages in Hama province, where four people were killed
- al-Ashara town in the eastern province of Deir Ezzor, with two civilians and a rebel fighter killed
- the north-west city of Idlib, where a woman and a teenager were shot dead
These reports cannot be independently verified, as Syria severely restricts journalists' freedom of movement.Regime 'struggling'
Abdelbaset Sayda, a Kurd, replaced Burhan Ghalioun, who had held the post since the group was established last September.
As the midday call to prayers began across the city of Homs, it found itself competing with a steady stream of thumps as mortar rounds slammed into the old city area.
For several hours, big black plumes of smoke drifted across the skyline. Every minute or so, another puffed up from the ground, often followed by a small burst of machine-gun or small-arms fire.
Standing on the roof of the UN headquarters was one of their monitors who told me to listen carefully to a whirring sound overhead. That, he told me, was an unmanned surveillance drone searching for targets for the mortar rounds to attack.
The UN has been trying for two days to get access to the old city but without success. As I drove into town, I could see the road to the area was blocked by an army checkpoint.
The old city is a civilian area and it's almost certain, having seen the size of the barrage, that injuries must have occurred.
How many will only be known when and if the UN get in to see for themselves.
He told the BBC World Service the SNC was not calling for "a foreign war or intervention. Rather it is the regime that is pushing our country in this direction, that is waging unjust war on the nation and the people".
"Our intentions are peaceful, but this bestial regime is bent on extermination and a scorched earth policy."
Mr Sayda, who lives in exile in Sweden, said the situation in Syria was "entering a sensitive phase", and that President Bashar al-Assad's regime was "on its last legs", AFP reported.
"The multiplying massacres and shellings show that it is struggling," he told the news agency.
He also urged "all officials in the regime and in the institutions to defect".
The BBC's Jim Muir in Beirut in neighbouring Lebanon says there have been some defections going on all along but very few by way of whole army units or politically from the regime.
On Sunday an air defence base north of Homs - a unit of about 100 people - defected en masse, before the military sent in helicopters to destroy the base to prevent missiles falling into rebel hands, according to opposition activists.
Since its inception, the SNC has been plagued by divisions and complaints from activists that it is ineffectual.
There have also been accusations that the council, which is an umbrella organisation for opposition groups, is dominated by Islamists and not inclusive enough.
However, Mr Sayda said any post-Assad Syria would reach out to its patchwork of ethnic groups.
"We would like to reassure all sects and groups, especially Alawites and Christians, that the future of Syria will be for all of us," he said.'Damascus clashes'
At least 32 civilians were killed across Syria in continuing violence on Sunday, opposition activists said, with at least 20 deaths in Homs province alone.
They said the army used artillery, mortars and rockets against opposition positions in the city of Homs, and in the towns of Qusair, Talbiseh and Rastan, Reuters news agency reported.
Security forces also targeted rebels in suburbs of the capital, Damascus, the agency quoted opposition sources as saying.
Sixteen soldiers were killed by rebels, according to the Syrian Observatory for Human Rights.
The UN says that at least 10,000 people have been killed since the uprising against Mr Assad began in March 2011.