Unrest against President Bashar al-Assad’s rule began in March 2011
Within months it escalated into a de-facto civil war
Rebel forces include the Free Syrian Army – formed by army deserters – as well as jihadist groups
Damascus describes the rebels as foreign-funded “armed gangs”
Neither side has the upper hand. The largest rebel-held areas are currently to the north and east of Aleppo and between Idlib and Hama
The political opposition remains divided despite the formation of a Syrian National Coalition in November
More than 70,000 people have died since 2011, UN estimates
The decision to boycott international diplomatic meetings in Syria effectively torpedoes the initiative launched by SNC leader Moaz al-Khatib, the BBC’s Jim Muir says.
Three weeks ago he announced that he was ready to meet Syrian government representatives to discuss an end to the violence.
The initiative was strongly backed by international powers including Russia and he was invited to Washington and Moscow. Now those visits will not take place.
The SNC will also boycott the Rome meeting of the mainly western Friends of Syria group, which supports the opposition.
It is particularly enraged by the use of Russian-supplied Scud missiles to bombard rebel-held areas of Aleppo – Syria’s biggest city.
“Hundreds of civilians have been killed by Scud missile strikes and Aleppo is being systematically destroyed,” the SNC statement said.
The decision to pull out of talks has dismayed diplomats, BBC correspondent Jim Muir says.
But opposition leaders are clearly worried that the SNC risks being discredited and losing touch with realities on the ground if it gets drawn into a diplomatic process involving compromise with a regime that shows no sign of readiness to step down, he adds.