Germany expects Russian leaking to start in 'weeks'

De Maiziere said the material “could be published in the coming weeks,” the Reuters news agency reported.

Maassen said Russia’s intention was “to damage trust in and the functioning of our democracy so our government should have domestic political difficulties and not be as free to act in its foreign policy as it is today.”

A hacker group, called APT28, said by US intelligence to be a front for Russian spies, stole 16 gigabytes of data from over 5,600 computers in the German parliament in 2015.

It broke into the accounts of 16 MPs and some in chancellor Angela Merkel’s office.

Recalling Russia’s actions in the US and French elections, De Maiziere said he expected "a classic disinformation campaign with lies and half truths intended to shape opinions" that would be spread by online "bots".

Mainstream parties are polling miles ahead of pro-Kremlin ones, such as The Left party and the far-right Alternative for Germany party.

The German voting system is also hard to hack. People vote on paper ballots and the Federal Statistics Office counts data on an encrypted, offline network.

But Germany hosts three pro-Kremlin media - RT Deutsch, Sputnik Deutsch, and NewsFront Deutsch.

The 2.5 million Russian people living in Germany also follow Russian state media, which has been broadcasting anti-Merkel propaganda for years.

Maassen, the intelligence chief, said on Tuesday: “It [Russia’s campaign] 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.”

Turkey, China

The yearly intelligence assessment by Germany’s domestic agency, the BfV, which handles counter-espionage, said Russia, Turkey, and China were its main adversaries.

“It is assumed that Russian state agencies are trying to influence parties, politicians and public opinion, with a particular eye to the 2017 parliamentary election,” it said.

It said “since 2014, propaganda and disinformation activities to promote Russian interests and defame the Federal Government’s policy have increased”.

“Important propaganda and disinformation tools include social networks, the microblogging service Twitter, government-funded and private institutes and Russian state … TV, radio, and online channels”, it said.

It said Turkey was spying on Turkish expats in Germany and China was trying to recruit agents on Facebook for economic espionage.

"The consequences for our country range from weakened negotiating positions to high material costs and economic damage all the way to impairment of national sovereignty," the BfV report said.

Terrorist threat

Russia’s propaganda campaign has portrayed Merkel’s open-door policy toward refugees as a security threat to German people.

It is also suspected of cultivating links with neo-Nazi thugs who could cause trouble in the run-up to the vote.

Maassen said the threat of further terrorist incidents, which could be exploited by Russia for political gain, remained high.

“Further attacks by single persons or terror commando groups must be expected,” he said.

The BfV report said there were some 24,000 “potential” Islamist extremists living in Germany compared to 8,350 in 2015.

De Maiziere said 680 of them posed a terrorist threat.

The BfV report added that there were 12,100 far-right radicals and 28,500 far-left extremists in the country.