Turkey scrambled fighter jets along its border with Syria on Monday after Syrian government forces bombed rebel positions in the frontier town of Ras al-Ain and stray shells flew into Turkish territory, Turkish security sources said.
Rebels overran Ras al-Ain almost a month ago in fighting which has triggered some of the biggest refugee movements of Syria's 20-month civil war, and has tested Turkey's resolve to defend itself against any spillover of violence.
The security sources said Turkish F-16 jets were scrambled from their base in the southeastern city of Diyarbakir after the air raids on the Free Syrian Army's headquarters in Ras al-Ain.
Shells landed in the Turkish town of Ceylanpinar, which abuts Ras al-Ain, triggering panic, the sources said. It was not immediately clear whether the shells were fired by forces loyal to President Bashar al-Assad or by the rebels. Turkey, a major backer of Syria's opposition, has asked NATO for Patriot surface-to-air missiles to be positioned near its 900-km (560-mile) border with Syria as a defensive measure.
Ankara is concerned about its neighbour's chemical weapons, the growing refugee crisis on its border, and what it says is Syrian support for Kurdish militants on its soil.
(Reporting by Seyhmus Cakan; Writing by Nick Tattersall)