An unknown person leaked German politicians’ credit card details, private communications, and other data last month — along with data from rappers and other media figures. The leak includes information from the office of Chancellor Angela Merkel and reportedly from people across all political parties in Germany’s parliament, except the far-right party Alternative for Germany.

German news outlet RBB first reported the news this morning. According to The Associated Press, a jumble of files was linked on a now-suspended Twitter account, which had around 17,000 followers. German cybersecurity agency head Arne Schönbohm said that the leak included details from around 1,000 people, and that one political party in parliament was not affected, although he didn’t confirm which.

The data dump was released throughout December, but only noticed now

The information was revealed in the form of an Advent calendar throughout December. Through the first half of the month, the Twitter account leaked details about rappers and TV presenters, according to the BBC. It began linking to data from politicians later that month, with its last post on December 28th. However, some reports — including the BBC’s — have said authorities didn’t become aware of it until yesterday. Schönbohm told the Associated Press that his agency had known about individual leaks in December, but that the data dumps had only been “posted online on large scale” yesterday.

Martina Feitz, a spokeswoman for Merkel’s office, said, “It appears, at first sight, that no sensitive information and data are included in what was published, including regarding the chancellor.” Feitz also warned the Bild that the leaks might contain falsified information, something Schönbohm didn’t rule out, although he said some details had been confirmed. “The German government is taking this incident very seriously,” said Feitz.

Among other details, the leak reportedly contained copies of letters sent to and from Merkel, private family chats from Greens Party leader Robert Habeck, and financial account information from Social Democratic Party member Florian Post — although Post also said that he’d seen at least one fake message. Justice Minister Katarina Barley called the attack a “serious” one. “The people behind this want to damage confidence in our democracy and institutions,” she said.

Germany’s government has suffered multiple cyberattacks in recent years, and it’s previously blamed Russian state-sponsored hackers. Last year, domestic intelligence agency head Hans-Georg Maassen accused Russia of trying to gather data for political influence campaigns, comparing the attacks to hacks on the American Democratic National Committee during the 2016 elections.

But for this recent leak, Schönbohm said that investigators are still determining who might be responsible for the attack. It’s also not clear whether this was an external attack or a leak from inside the agency. The Guardian reports that an interior ministry spokesperson didn’t rule out either possibility.