TBILISI, Georgia — The presidents of Turkey, Azerbaijan and Georgia gathered for a Tbilisi summit on Tuesday to discuss trilateral cooperation.Turkish President Abdullah Gül said the three countries had contributed to the stability and welfare of the Caucasus, adding: "The high mountains of the Caucasus are no longer a barrier but a cooperation area."This was echoed by Georgia's President, Giorgi Margvelashvili who said: "Our cooperation is very long standing, intensive, result-oriented and positive for the three countries and the region."Azerbaijani President Ilham Aliyev said the trilateral cooperation has "common regional and global purposes".The three countries launched the Baku-Tbilisi-Kars regional rail link project in 2007 which will directly connect Turkey, Georgia and Azerbaijan; construction is expected to be completed in mid-2015.