BERLIN (Reuters) - A German court said it had ordered the Bavarian sister party of Chancellor Angela Merkel's Christian Democrats to remove a fake tweet issued in the name of top Social Democrat Martin Schulz or face a fine of up to 250,000 euros ($291,375).
There has been growing tension between the conservatives and the center-left SPD led by Schulz, former president of the European Parliament, ahead of Germany's national elections on Sept. 24.
Merkel's Christian Democrats (CDU) and the SPD are partners in the current "grand coalition" government, but are vying for enough votes to govern with other partners next time around.
A court spokesman said Schulz had asked for an injunction after the CSU youth wing sent out a tweet under the fake account "@therealMartinSchulfter" following clashes between militant leftists and police at the recent G20 summit in Hamburg.
German officials have expressed growing concern about "fake news" and falsified information in the run-up to the election, although most of the attention has focused on possible meddling by Russia, not domestic Twitter spoofers.
Spokesman Kai Wantzen said the Hamburg court on Monday banned the CSU from publishing or distributing a July 10 tweet that falsely suggested Schulz would form a coalition with the far-left Left party and seemed to minimize the leftist violence.
Schulz does not use the Twitter handle used by the CSU, but the fake tweet was published in tandem with an authenticated tweet, which made it difficult to tell the difference.
Hubertus Heil, secretary general of the SPD, told the weekly newsmagazine Der Spiegel he welcomed the ruling, calling it "scandalous" that conservatives had tolerated such behavior.
Heil said the SPD wanted a "tough but fair election campaign, but that cannot rely on defamation and fake news."
Arne Schoenbohm, president of the German federal cyber protection agency, told Reuters that government officials were bracing for disinformation and propaganda campaigns ahead of the election. He said any data dumps from previous cyber hacks were only likely to emerge in the week before the poll.
Schoenbohm said political parties were sensitized to the increased risk, and a growing number of political candidates were asking BSI to help them set up verified accounts with two-factor identification with Facebook and Google.
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(Reporting by Andrea Shalal; editing by Mark Heinrich)