Moscow, increasingly economically reliant on China since invading Ukraine in 2022, has pushed for the pipeline for years, but progress has been slow amid hesitation in Beijing.

Kremlin spokesman Dmitry Peskov told Russian media that while the two sides had reached a “basic understanding”, including on “the route and how it will be built”, there was no “clear timeline” and “there are still some details to be worked out”.

The project was not mentioned in the Kremlin’s long list of agreements published on its website after the Putin-Xi talks.

The pipeline would carry 50 billion cubic metres a year of gas, and – crucially for Russia – the supplies would come from fields that used to serve Europe, where exports have plunged since the war.

The route would run 2,600km (1,600 miles) from the Yamal Peninsula in northern Siberia through Mongolia into China.

China has shown less enthusiasm for the project, something Russia had hoped would change with the energy instability triggered by the Middle East war.