Hundreds of German politicians have had personal details hacked and published online, reports say.
Contact information, private chats and credit card details have been put out on Twitter which belong to national and local 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.
The true extent of damage caused by the leak is not yet known.
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 appeared to be linked to an internet platform based in Hamburg, he said.
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.