The German government demanded speedy answers on July 12 from industrial conglomerate Siemens, after two of the group's gas turbines were delivered to Russian-annexed Crimea despite sanctions imposed by the European Union.
Chancellor Angela Merkel's spokesman Steffen Seibert told journalists in Berlin that the government was following the case "with great attention," adding, "right now, the facts of the matter need to be clarified as quickly and comprehensively as possible."
"That's the Siemens company's responsibility above all," Seibert said.
Siemens said July 10 that two gas turbines it had sold for a power plant in Russia last year had been diverted to the Ukrainian region of Crimea.
The region has been subjected to EU sanctions on energy technology since Russia illegally annexed it from Ukraine in 2014.
Siemens said the transfer a "clear breach of Siemens' delivery contracts" and has filed a lawsuit against a Russian state firm after the two turbines turned up in Crimea.
Seibert said: "I would point out that it's the company's job to check whether their business falls under a sanctions regime."
"The delivery of the turbines into Crimea against the terms of the contract, against high-ranking assurances, is ... remarkable and completely unacceptable," Seibert added.
Based on reporting by Reuters, AFP, AP, and dpa