A meeting of the High Level Working Group on gas interconnectivity in Central and Southeast Europe took place in Budapest, Hungary. A major accent in the talks was the strengthening of regional cooperation and also the guaranteeing of security and diversification of gas supplies in the electricity sector too. A Declaration was signed for the providing of an uninterrupted two-way gas connection between Bulgaria, Romania, Greece and Hungary. A so-called vertical corridor will have to be built between the four states, in order for this goal to be achieved. A memorandum was also signed between gas transferring operators of Bulgaria, Greece, Romania and Ukraine for the provision of technical and commercial prerequisites for the introduction of two-way natural gas supplies via the Trans-Balkan gas pipeline by 2019.