Turkey-backed Free Syrian Army fighters are seen at a training camp in Azaz, Syria January 21, 2018. REUTERS/Osman Orsal

Riot police detain a demonstrator during a protest against Turkey's military operation in Syria's Afrin region, in Istanbul, Turkey January 21, 2018. REUTERS/Umit Bektas

A Turkey-backed Free Syrian Army fighter takes up position near Menagh, Syria January 21, 2018. REUTERS/Osman Orsal

Municipality workers clean up a street in front of a building which was hit by rockets fired from Syria, in the border town of Reyhanli in Hatay province, Turkey January 22, 2018. REUTERS/Umit Bektas

Kurdish protesters hold flags during a protest in front of the Russian embassy in Beirut, Lebanon January 22, 2018. REUTERS/Jamal Saidi

Smoke rises from the Syria's Afrin region, as it is pictured from near the Turkish town of Hassa, on the Turkish-Syrian border in Hatay province, Turkey January 20, 2018. REUTERS/Osman Orsal

Turkey-backed Free Syrian Army fighters are seen at a training camp in Azaz, Syria January 21, 2018. REUTERS/Osman Orsal

A Turkey-backed Free Syrian Army fighter holds a makeshift Turkish flag as he patrols on a road near Azaz, Syria January 21, 2018. REUTERS/Osman Orsal

Turkish soldiers and tanks are pictured in a village on the Turkish-Syrian border in Gaziantep province, Turkey January 22, 2018. REUTERS/Osman Orsal

Turkish tanks take position in a village on the Turkish-Syrian border in Gaziantep province, Turkey January 22, 2018. REUTERS/Osman Orsal

Riot police block the entrance of pro-Kurdish Peoples' Democratic Party (HDP) office in order to prevent party members to go out for a demonstration in the southeastern city of Diyarbakir, Turkey, January 21, 2018. REUTERS/Sertac Kayar

Turkey-backed Free Syrian Army fighters on a truck leave from a training camp in Azaz, Syria January 21, 2018. REUTERS/Osman Orsal

Turkey-backed Free Syrian Army fighters on trucks leave from a training camp in Azaz, Syria January 21, 2018. REUTERS/Osman Orsal

A Turkey-backed Free Syrian Army fighter stands guard in Azaz, Syria January 21, 2018. REUTERS/Osman Orsal

Turkey-backed Free Syrian Army fighters pray at a training camp in Azaz, Syria January 21, 2018. REUTERS/Osman Orsal

Riot police detain a demonstrator during a protest against Turkey's military operation in Syria's Afrin region, in Istanbul, Turkey January 21, 2018. REUTERS/Umit Bektas

Turkey-backed Free Syrian Army fighters are pictured at a check point near Azaz, Syria January 21, 2018. REUTERS/Osman Orsal

A Turkey-backed Free Syrian Army fighter takes up position near Menagh, Syria January 21, 2018. REUTERS/Osman Orsal

A Turkey-backed Free Syrian Army fighter takes up position near Menagh, Syria January 21, 2018. REUTERS/Osman Orsal - RC1D31ED0FD0

A Turkey-backed Free Syrian Army fighter is seen near Menagh, Syria January 21, 2018. REUTERS/Osman Orsal

Turkish soldiers and tanks are pictured in a village on the Turkish-Syrian border in Gaziantep province, Turkey January 22, 2018. REUTERS/Osman Orsal

Boys stand in front of a building which was hit by rockets fired from Syria, in the border town of Reyhanli in Hatay province, Turkey January 22, 2018. REUTERS/Umit Bektas

Turkish soldiers stand on top of a tank in a village on the Turkish-Syrian border in Gaziantep province, Turkey January 22, 2018. REUTERS/Osman Orsal

Municipality workers clean up a street in front of a building which was hit by rockets fired from Syria, in the border town of Reyhanli in Hatay province, Turkey January 22, 2018. REUTERS/Umit Bektas

A Turkish police officer secures the area after a building was hit by a rocket fired from Syria, in the border town of Kilis, Turkey January 22, 2018. REUTERS/Osman Orsal

Police forensic experts examine a building which was damaged after a rocket fired from Syria landed nearby, in the border town of Kilis, Turkey January 22, 2018. REUTERS/Osman Orsal

Turkey-backed Free Syrian Army fighters are seen at a training camp in Azaz, Syria January 21, 2018. REUTERS/Osman Orsal

Riot police stand guard during a protest against Turkey's military operation in Syria's Afrin region, in Istanbul, Turkey January 21, 2018. REUTERS/Umit Bektas

Turkey-backed Free Syrian Army fighters patrol near Menagh, Syria January 21, 2018. REUTERS/Osman Orsal - RC1B5D78A5E0

A Turkey-backed Free Syrian Army fighter is seen in a village on the Turkish-Syrian border in Gaziantep province, Turkey January 22, 2018. REUTERS/Osman Orsal

Men hold up the sign of Turkish Cypriot newspaper Afrika, which was attacked by supporters of Turkish President Tayyip Erdogan on Monday over the newspaper’s headlines criticising the Turkish army’s campaign in Afrin in northern Syria, in the Turkish-administered northern part of Nicosia, Cyprus January 22, 2018. REUTERS/Yiannis Kourtoglou??