The Insider and Der Spiegel published an investigation into an alleged Russian sabotage operation targeting Leipzig airport.
The authors of the investigation said they examined phone records, travel data and information from European law enforcement agencies and found documentary evidence linking the operation to Russian military intelligence.
The Insider also said it identified several previously unknown alleged operatives who had appeared in other sabotage episodes in Europe.
German authorities had previously said there were indications of Russian involvement in similar operations.
The conclusion that the GRU was involved is based on the journalistic investigation and law-enforcement material; it is not a final legal finding established by a court.