ISTANBUL - Turkish President Tayyip Erdogan accused Kurdish groups on Saturday of trying to grab control of northern Syria, and said Ankara would not allow this to happen.In a speech in southeast Turkey, Erdogan denounced the merging of the Syrian town of Tel Abyad last week into an autonomous political structure created by the Kurds."All they want is to seize northern Syria entirely," Erdogan said. "We will under no circumstances allow northern Syria to become a victim of their scheming. Because this constitutes a threat for us, and it is not possible for us as Turkey to say 'yes' to this threat."Turkey is alarmed by territorial gains for the Kurds in Syria's civil war, which it fears could stir separatism among its own Kurdish minority.Tel Abyad, on the border with Turkey, was captured in June from Islamic State by Kurdish YPG militia with help from U.S.-led air strikes. Last week, a local leadership council declared it part of the system of autonomous self government established by the Kurds.Syrian Kurds have established three autonomous zones, or "cantons', across northern Syria since the civil war broke out in 2011. They deny aiming to establish their own state.The YPG's capture of Tel Abyad linked up the Kurdish-controlled canton of Kobani, which was besieged by Islamic State last year, with the bigger canton of Jazeera, which is further east and borders Iraq.Turkey has for the past three decades been trying to end an insurgency by fighters of the Kurdistan Workers Party (PKK), which is classified as a terrorist organization by the United States and European Union.The PKK has been staging almost daily attacks in the southeast since July, when a ceasefire fell apart.Ankara accuses the Syrian Kurds' political arm, the PYD, of deep links to the PKK. It has been incensed by the role the Kurds have carved out for themselves, with U.S. support, in the fight against Islamic State in northern Syria.