"Russia should revise the refusal of visa for Mr. Seppelt. Otherwise, there is a reasonable suspicion that Russia either has something to hide or has a problem with transparency and fair play in sports, or both," Roettgen said, as quoted by Der Tagesspiegel newspaper.
On Friday, the ARD broadcaster said that Russia had not given visa that is required for attending the 2018 FIFA World Cup Finals to Seppelt, who is employed by the channel and has worked on several documentaries on doping in Russian sport.
"This can be regarded as a violation of the right to freedom of information. Although I can not call Seppelt a journalist, he has violated all the principles of objective journalism in his work, in fact, he is a real propagandist who fulfills the task of 'exposing and destroying' Russian athletes," Solovyov said, as quoted by the union's press service.
Following the release of Seppelt's first film, the World Anti-Doping Agency (WADA) launched an investigation into the allegations of doping abuse in Russian sports. In November 2015, WADA's Independent Commission issued a report accusing Russia of numerous breaches of global anti-doping regulations.
Russia's first-ever FIFA World Cup Finals will be held between June 14 and July 15 in 11 cities across the country.