A senior executive at Russian gas company Gazprom said on Wednesday that the company is still waiting for the return of the Siemens Energy turbine for the Nord Stream 1 gas pipeline, blaming the German company for the delay.

Siemens Energy said it is up to Gazprom to provide the necessary customs paperwork to return the turbine after maintenance in Canada.

Russia pointed to turbine issues as the reason for cutting gas supplies via Nord Stream 1 – the main gas link to Europe – to only 20 percent of its capacity as of Wednesday.

The European Union accused it of energy blackmail, which Moscow denies, as the two sides exchange economic blows and hostile rhetoric over the war in Ukraine.

Vitaly Markelov, Gazprom’s deputy CEO, told Russian channel 24: "We have been relying on receiving one repaired engine from Siemens (Energy) since May, but to this day we have not received this engine."

He said more turbines need repair but “Siemens is not providing work to solve these problems.”

Siemens Energy confirmed that the transfer of serviced turbines can start immediately.

"The German authorities have provided Siemens Energy with all the documents necessary to export the turbines to Russia.

The supply reductions hinder the European Union’s efforts to build gas reserves before next winter, increasing the risk of shortages and rationing.

Russia says it is a reliable supplier of oil and gas, and the issues related to turbine repairs and returns are an example of the economic sanctions' blowback on the West.