Violence is continuing in Syria, with activists reporting government assaults on the southern city of Deraa and Homs in the centre of the country.
Activists in Homs said several neighbourhoods were under intense shelling for the third day in a row on Saturday. They said al-Khaldiyeh, Jouret al-Shayyah, al-Qusour and Old Homs were being bombarded with mortars and rockets.
At least six people were reportedly killed. Military reinforcement were reported to have arrived to the city, including armoured vehicles and dozens of pickups equipped with machine guns.
Opposition strongholds in the city has been under shelling for many months, but activists said the intensity had increased significantly in recent days.
The nearby town of al-Qusayr was also said to be enduring heavy shelling and a large number of buildings and agricultural areas were burning as a result.
Homs province has been the scene of large anti-government protests and has also become a stronghold for the armed opposition.
In the city of Deraa, where the uprising against President Bashar al-Assad's rule erupted 15 months ago, activists said 17 people, including 10 women, were killed overnight by shelling.
The UK-based Syrian Observatory for Human Rights, which monitors violence in Syria through a network of sources inside the country, reported fighting in the town between the army and opposition fighters after the shelling.
The Observatory said three soldiers died in clashes in the north of the country and four rebels were also reported killed.
The UN says that well over 10,000 people have been killed since the uprising began in March 2011.
Situation 'more alarming'
In the latest diplomatic development, Russian Foreign Minister Sergei Lavrov said his country would not approve the use of force against the Syrian regime at the United Nations
"We will not sanction the use of force at the United Nations Security Council," Lavrov said in televised remarks.
Lavrov said "the situation is becoming more alarming", but stressed that there is no alternative to a peace plan mediated by UN-Arab League envoy Kofi Annan to stop the violence.
He said Russia was calling for a working group to pressure all parties of the conflict to implement the plan, which calls for a Syrian-led political transition.
Russia, along with China, has vetoed two Security Council resolutions against Assad and have vowed to oppose any military intervention.
Meanwhile, in Turkey, the Syrian National Council (SNC), the main opposition bloc, is holding a two-day meeting to choose a new president.
Its former head, Burhan Ghalioun, resigned from his post amid accusations that he was monopolising power and was out of touch with the opposition on the ground.
Al Jazeera's Anita McNaught, reporting from Istanbul, said the SNC has unofficially selected Abdulbaset Sieda, a Kurdish candidate, to follow on from Ghalioun. A vote may not take place if there is consensus on Sieda.
'Yet another academic'
Our correspondent said it was unlikely that people in Syria would feel that he represents them to a larger extent than Ghalioun did.
"He's yet another of those exiled academics, a philosophy professor who lived outside the country for some 18 years, more than a decade in Sweden," she said.
"People inside Syria feel that they have had to suffer and pay with blood while the SNC has set in hotels, holding meeting after meeting which hasn't yielded anything significant to help people.
She said he would also face challenges in terms of internal politics within the council.
"The election of a Kurd, some critics say, will make it look like the SNC is more responsive to Syria's minorities. But they'll also tell you he's only there because he has the backing of the Islamist faction in the SNC which other critics of the council say is the one that actually wields the power and calls the shots behind the scenes."
'Stench of burnt flesh'
In the latest call for action to end the violence on the ground, Annan called on Friday for "additional pressure" on the Syrian leadership in the wake of a new massacre as he held talks in the US.
Activists say at least 70 people were killed on Wednesday in an assault on al-Qubayr, a small farming village in Hama province of about 160 people, mostly Bedouins.
UN observers who visited the village said they saw blood on the walls and were hit by the smell of the "stench of burnt flesh" but could not confirm how many had died.
While the government denied responsibility, Martin Nesirky, a UN spokesman, said on Friday the observers saw armoured vehicle tracks around homes in the village, that was damaged by rockets, grenades and various other weapons.
"Inside some of the houses, blood was visible across the walls and floors. Fire was still burning outside houses and there was a strong stench of burnt flesh," Nesirky said.
UN officials have made it clear they believe government forces and allies were behind the attack on the mainly Sunni Muslim village surrounded by an Alawite population loyal to Assad.
Diplomats said on Friday that the UK, France and US will quickly draw up a Security Council resolution proposing sanctions against Syria over the worsening conflict.