Moscow, July 28 : Russia's gas giant Gazprom has said that Siemens failed to fulfill its obligations and had not returned a repaired turbine engine for the Nord Stream 1 pipeline. "Back in May, we expected to receive one repaired engine from Siemens, but to date we have not received this engine," local media reported citing Vitaly Markelov, Deputy Chairman of the Management Committee of Gazprom, on Wednesday. "Open questions still remain in relation to sanctions risks, which prevent the return of this gas turbine engine to Russia, and the transportation of other engines for repair," he added. According to Markelov, problems remain with unrepaired engines at the compressor station, and "Siemens is not carrying out work to eliminate these problems". He said that six gas pumping units are usually used at the compressor station, and only one engine is in working order while the rest are not working due to technical problems, Xinhua news agency reported. He added that the company hadn't experienced problems with the repair of the engines prior to the imposition of anti-Russian sanctions. /IANS