Syrian government forces bombed rebel positions in the town of Ras al-Ain on the border with Turkey on Monday, leaving at least 12 dead according to rebel activists.
Shells and anti-aircraft fire shook the Turkish town of Ceylanpinar although no-one there reported injured.
Turkish ambulances rushed to the scene taking at least 11 wounded people from the Syrian side to hospital.
Meanwhile Turkey scrambled F-16 fighter jets along the frontier as a warning to Damascus not to breach its territory.
Almost a month ago rebels overran the town causing one of the biggest refugee movements in the 20-month-conflict.
At the same time, responding to US concerns the Syrian government said on Monday that it will not use chemical weapons on its own people.