Turkey has banned Syrian flights from its airspace in a tit-for-tat move, while Iran handed a "detailed proposal" to UN-Arab League envoy Lakhdar Brahimi aimed at ending the conflict between the Syria's army and rebels.
The US has denounced Russia's policy of aiding the Syrian regime as "morally bankrupt," as tensions between Damascus and Ankara escalate over cargo seized from a Syrian passenger plane.
The war of words between Syria and Turkey escalated on Thursday when Ankara said it had found military supplies on a passenger plane it intercepted en route between Moscow and Damascus.
Turkey seized "objectionable cargo" aboard a Syrian passenger plane which it intercepted en route from Moscow to Damascus on Wednesday, Turkish Foreign Minister Ahmet Davutoglu said.
Regime aircraft hammered insurgent bastions nationwide on Sunday as rebels said they now control most of the country and have moved their command centre from Turkey to "liberated areas" inside Syria.
War-torn Syria's frustrated neighbor Turkey demanded on Thursday that world powers set up refugee camps within the country to stem the massive outflow of refugees fleeing the fighting.
US Secretary of State Hillary Clinton arrived Saturday in Istanbul for talks on the conflict in Syria with Turkish leaders after Washington slapped fresh sanctions on Bashar al-Assad's regime and its allies.
As Europe battles its never-ending debt crisis, Turkey, with its flourishing economy, is increasingly attracting the attention of German companies, as well as German-born Turks in search of a job.