MOSCOW, June 28 (Reuters) - Russia's Gazprom will start annual pipeline gas exports to China of 10 billion cubic meters (bcm) in 2027, its boss Alexei Miller told an annual shareholders' meeting on Friday.

He also said the Power of Siberia pipeline to China, which started operations in late 2019, will reach its planned capacity of 38 bcm per year in 2025.

Gazprom has been trying to boost gas exports to China, with the efforts acquiring urgency after its gas exports to Europe, where it used to generate around two-thirds of its gas sales revenues, collapsed in the wake of Russia's conflict in Ukraine.

In February 2022, just days before Russia sent its troops to Ukraine, Beijing agreed to buy gas from Russia's far east island of Sakhalin, which will be transported via a new pipeline across the Japan Sea to China's Heilongjiang province.

Russia has also been in talks for years about building the Power of Siberia-2 pipeline to carry 50 billion cubic meters of natural gas a year from the Yamal region in northern Russia to China via Mongolia. This would almost match the volumes the now idle Nord Stream 1 pipeline that was damaged by explosions in 2022 used to carry under the Baltic Sea.

The negotiations have not been concluded due to differences over numerous issues, mainly about the price of gas. (Reporting by Vladimir Soldatkin; editing by Jason Neely and Emelia Sithole-Matarise)