Metropolitan, which signed the agreement on June 27, received nine offers in the public procurement procedure for awarding the contract. It launched a tender in May for the design of a section connecting Lyulin station, in the western part of the city, to the Sofia ring road.

Earlier in June, the European Investment Bank (EIB) said Sofia was seeking a €22m loan to finance the construction of the second stage of the city's metro Line 3, which envisages the construction of a 3.8km twin-track metro section and four stations.

Line 3 is expected to be 16km in total, with 19 stations. When completed, it will bring the Sofia metro network to 56km and 53 stations.