Turkish President Recep Tayyip Erdogan told Russian counterpart Vladimir Putin on Sunday that it was imperative the Kremlin “clear” Kurdish forces from northern Syria. Erdogan has been threatening to launch a new incursion into northern Syria to push out Kurdish forces he blames for a November bomb blast that killed six people in Istanbul. A 2019 agreement between Moscow and Ankara ended another offensive by setting up a 30-kilometre (19-mile) “safe zone” to protect Turkey against cross-border attacks from Syrian territory. Erdogan accuses Russia — a key player in the Syria conflict which bac…