The pipeline, running between Siberia and the northeastern Chinese city of Daqing, will allow a rapid increase in oil exports between the two countries.

Until now, Russian oil has been transported to China by rail.

Concentrated in western Siberia, Russia's network of pipelines for oil exports has so far run towards Europe.

Russia is expected to export 15m tonnes of oil through the new pipeline each year during the next two decades - about 300,000 barrels a day.