The first gas deliveries to Europe are expected in late 2019.

"Russia and Turkey signaled on Tuesday that they would resuscitate the development of a natural-gas pipeline between them, potentially undermining European efforts to reduce reliance on Russian energy with fuel piped in from Azerbaijan," the Wall Street Journal reports

The pipeline, known as TurkStream, would bring gas from Siberia under the Black Sea. The project was sidelined after Turkish jets shot down a Russian warplane near the Syrian border in November, causing a diplomatic rupture.

The EU views the development of a southern gas corridor, a 2,200-mile network that starts at the Caspian Sea and ends in Italy, as vital for diversifying Europe