The US and Russian military will begin discussions “as soon as possible” to avoid direct clashes in the air above Syria, top diplomats have said.
Russia has begun air strikes against rebel positions within Syria, with the first target near the western city of Homs, US defence officials say.
Syria has reportedly given Russia “material evidence” that opposition fighters have used chemical weapons during the ongoing civil war.
Assad’s government are increasingly preventing humanitarian aid and medical supplies reaching opposition-controlled areas of the country.
The high number of killings committed outside the law in Syria by all sides of the conflict visualise the failure of the judiciary system and the underlying major human rights crisis in the country.