ANKARA (Reuters) - Turkey could open its border gates to Armenia if Yerevan takes positive steps for regional peace, President Tayyip Erdogan said on Thursday, adding he discussed forming a six-country regional cooperation platform with his Azeri counterpart. Erdogan, in Baku to mark Azerbaijan’s victory in a war over the disputed Nagorno-Karabakh enclave, earlier renewed a call for a change of leadership in Armenia. Speaking alongside Azeri President Ilham Aliyev, Erdogan said he took issue with Armenia’s leadership not its people. Armenia could participate in the planned regional platform along with Turkey, Russia, Iran, Azerbaijan and Georgia if it contributed to regional peace, he said.