German Chancellor Angela Merkel alongside hundreds of politicians have had their personal details hacked and published online.
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 were also 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 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.
A government spokeswoman said no sensitive data from the chancellor’s office had been published.