Bulgarian Foreign Minister Nikolay Mladenov, along with his Romanian and Greek counterparts Titus Corlatean and Dimitris Avramopoulos are set to meet here on Monday in the Bulgarian capital of Sofia. During their trilateral meeting , the ministers will discuss a unified position towards the policy of widening European Union membership to include western Balkan countries. They will also touch on regional issues, border cooperation among countries of the region, and security of the EU borders.