International Syria envoy Lakhdar Brahimi on Tuesday travelled to Turkey as part of a regional tour, as opposition activists in reported heavy shelling in the Syrian capital and along the border with Turkey, dpa reported.
Diplomatic sources said Brahimi would hold talks with Turkish Prime Minister Recep Tayyip Erdogan.
"Helicopters and jets have been bombarding areas in al-Qadam, on the outskirts of Damascus killing six civilians," activist Mohammed al-Abdallah told dpa.
Activists said fierce fighting was taking place in at least two districts along the border in Syria's northern Aleppo and Idlib provinces. Four people were killed in the al-Shaar district, the activists said.
Brahimi, who became United Nations-Arab League envoy on Syria at the beginning of the month, is on his first official visit to the region.
The Algerian diplomat has already held talks with Arab League and Egyptian officials, Syrian President Bashar al-Assad and the opposition.