Hundreds of German politicians including Chancellor Angela Merkel have had personal details hacked and published online, reports say.
Contacts, private chats and financial details were put out on Twitter which belong to figures from every political party except the far-right AfD.
Data from celebrities and journalists also appear to have been leaked.
It is unclear who was behind the hack, which emerged on Twitter last month in the style of an advent calendar.
How extensive was the attack?
The true extent of damage caused by the leak is not yet known although Justice Minister Katarina Barley said it was a "serious attack".
"The people behind this want to damage confidence in our democracy and institutions," she said.
Germany's federal office for information security (BSI) said it was investigating the hack and said government networks were not affected, as far as it was aware. The national cyber-defence centre convened a meeting on Friday morning.
Although no politically sensitive documents appear to have been published, the sheer extent of personal data leaked suggests the consequences could be considerable, says RBB reporter Michael Götschenberg, who researched the hack.
The Twitter account, followed by 17,000 people, appeared to be linked to an internet platform based in Hamburg, he said. Although documents had been posted on the account last month, it was not until Thursday evening that officials became aware of the hack.
Bild newspaper said all the data stolen in the attack dated back to before October 2018 but it was not clear when it began.
Who was targeted?
National and local political figures as well as some TV personalities have had their details hacked. According to the reports, among those hit were:
- Chancellor Angela Merkel: her email address and several letters to and from the chancellor appear to have been published
- The main parliamentary groups including the ruling centre-right and centre-left parties, as well as The Greens, left-wing Die Linke and FDP. Only AfD appears to have escaped
- Greens leader Robert Habeck, who had private chats with family members and credit card details posted online
- Journalists from public broadcasters ARD and ZDF as well as TV satirist Jan Böhmermann, rapper Marteria and rap group K.I.Z
- Another TV satirist, Christian Ehring, had 3.4 gigabytes of data stolen and posted online, including holiday photos. Last year he won a court case brought by AfD leader Alice Weidel, who complained when he called her a "slut" on his TV show.
- Centre-left SPD MP Florian Post said he felt "quite shocked" by the leak of account statements and other details online, but he added that at least one file that had been posted was fake.
German politicians have been targeted before.
Russia was accused of a series of cyber attacks that stole data from computers in the German parliament, the Bundestag, in 2015.
Last year the German government's IT network came under a fresh attack amid reports that Russian hackers were also to blame.
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