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By Andrea Shalal

BERLIN, July 4 (Reuters) - Germany is expecting Russia to try to influence its general election on Sept. 24, but there are no indications of which party it would seek to back, officials said on Tuesday.

Interior Minister Thomas de Maiziere said at a news conference that data stolen in 2015 in a hack of the lower house of parliament could surface in the coming weeks.

Hans-Georg Maassen, the head of Germany's domestic intelligence agency, said that while it was not known what Russia would do he suspected that Russian President Vladimir Putin would prefer a different German chancellor than Angela Merkel.

It was likely that Russia had sought to influence the U.S. election and everything points to Moscow's involvement in efforts to influence the election in France, de Maiziere said.

"As a result, it cannot be excluded - and we are preparing internally - that there will be a similar effort to influence the election in Germany," he said.

Russia has denied trying to influence foreign elections.

Merkel, who backs continued sanctions against Russia for its actions towards Ukraine, is seeking a fourth term.

Sources have told Reuters that one of the dozen or so accounts hit in the 2015 Bundestag hack was Merkel's parliamentary account, although her primary work account was not touched.

Tuesday's comments come days before Putin arrives in Germany for a meeting of G20 leaders, and follow a spate of cyber attacks directed at the German parliament, individual lawmakers, political parties and think tanks affiliated with parties since summer 2015 - all of which German intelligence agencies blame on APT 28, a Russian hacker group with links to Moscow.

Russia denies it has been in any way involved in the cyber attacks.

Maassen said any campaign to influence the election could be more about unsettling German voters than promoting any particular candidate.

"It may not be aimed at strengthening one party or another, or ensuring that one or another person is elected to run the government, but that the trust in the functioning of our democracy is damaged," he said.

Maassen also said the German electoral system - which is based on written rather than electronic votes - was less vulnerable to electronic manipulation than other systems.

Maassen said his agency had no reliable evidence that a cyber attack that started in Ukraine last week and spread around the world was carried out by Russia.

Ukraine has blamed Russian security services for the attack, which it said was aimed at destroying important data and spreading panic. (Reporting by Andrea Shalal; Writing by Joseph Nasr, editing by Thomas Escritt/Jeremy Gaunt)