A consortium led by Bulgarian construction company Agromah is building the section under a contract worth just over €71 million, according to the regional development ministry.
Work is scheduled to end in August 2019.
The 156km Struma Highway runs from the capital Sofia to the border with Greece. Around 87km of the highway has been completed and in use. However, some sections of the route pass through difficult terrain and work has involved construction of viaducts and the tunnel sections.
Construction of the motorway has been divided into four sections, of which three have already been completed: the 17km Dolna Dikanya – Dupnitsa section, the Dupnitsa – Blagoevgrad section of around 37km and the nearly 15km section Sandanski-Kulata to the border with Greece.
In June, the government retendered work for the Zheleznitsa tunnel, a project expected to cost in the order of €128 million.
Bulgaria has started work on a 12.6km section of Struma motorway between the southwestern towns of Blagoevgrad and Krupnik.
