(File Photo)

A second line of the China-Russia oil pipeline began operation on Monday, raising China's annual imports of Russian crude oil from 15 million to 30 million tons.

Construction began in August 2016 on the 941.8-kilometer second line from Mohe, the northernmost point of China, which borders Russia, to the city of Daqing in Northeast China's Heilongjiang Province.

The line crosses North China's Inner Mongolia Autonomous Region.

The second oil pipeline was built in parallel with the first line between Mohe and Daqing, said Jiang Changliang, general manager of PetroChina Pipeline Company.

The project is intended to deepen energy cooperation between China and Russia and serve the China-proposed Belt and Road initiative.

Originating in the Russian town of Skovorodino, the new line enters China at Mohe. It operated smoothly and its transmission was 3,812 cubic meters per hour at the Mohe station.

The first line from Mohe to Daqing was put into use on January 1, 2011. It has transported a total of 110 million tons of crude oil so far.