China is helping Russia undertake its biggest military expansion since Soviet times, ramping up sales of machine tools, microelectronics and other technology that Moscow is using to produce missiles, tanks, aircraft and other weaponry for its war against Ukraine, according to a US assessment.

US officials are hoping the release of the intelligence will encourage European allies to press China, as the German chancellor, Olaf Scholz, heads to Beijing this weekend and G7 foreign ministers meet next week in Italy.

Announcing US findings, officials said China was helping Russia in the production of drones, space-based capabilities and machine-tool exports vital for producing ballistic missiles.

China has been the key factor in revitalising Russia’s defense industrial base, “which had otherwise suffered significant setbacks” since Russia’s invasion of Ukraine, a senior US official told reporters on condition of anonymity.

“Russia is undertaking its most ambitious defense expansion since the Soviet era and on a faster timeline than we believed possible early on in this conflict,” the official said.