Russian-linked online disinformation networks are spreading faked spy agency warnings of terrorist attacks in Germany ahead of this month's election in an apparent attempt to sow fear and depress voter turnout, cybersecurity experts say.

The networks were also spreading unfounded rumors aimed at discrediting Christian Democratic Union leader Friedrich Merz, a conservative whom polls place ahead of the second-placed, Russia-friendly Alternative for Germany (AfD) in polls, said the researchers.

The experts, working with German human rights organizations Civil Society Forum and Robert Bosch Foundation, are veterans of efforts to combat Russian influencing operations who did not wish to be identified for security reasons.