Bulgaria and Serbia have signed a memorandum of understanding to work together for the construction of a natural gas pipeline.
It will link the Balkan neighbours and help boost security of supplies and reduce their strong reliance on Russian gas.
The two countries plan to begin the construction of the 150-km gas interconnection link by May 2019.
They hope to have it operational by the end of 2020.
Bulgaria has already drafter a technical plan for the 61km of the pipeline which will link Sofia with the Serbian city of Nis.