Oil and gas contractor Saipem said it was not given formal notice the South Stream Offshore Pipeline contract would be scrapped.
Russia said the 40 billion euro pipeline link to Europe was to be dropped due to tension between the European Union and Moscow over the crisis in Ukraine.
Italian-quartered Saipem was contracted to build the four parallel gas pipelines by South Stream Transport BV in March 2014.
The project was expected to be completed in 2015.
Saipem has however said operational “activities will continue to progress.”