Germany's digital defense body is "intensively" investigating the apparent data leak that saw data of hundreds of politicians from across the political spectrum being published online, a spokesman for the Federal Office for IT Safety (BSI) said on Friday.

"Hacking attack against politicians: The BSI is currently intensively probing the issue in close cooperation with other federal institutions," the BSI said on Twitter, adding that "according to what we know so far" the government's confidential networks were unaffected.

The hack targeted all of Germany's political parties currently represented in the federal parliament, except for the far-right Alternative for Germany (AfD). The party confirmed to DW that it had not been affected.

Preliminary review of the documents discovered no sensitive information. However, the data published on Twitter included mobile phone numbers, contact info, and credit card details from members of Germany's major parties. The leak also included banking and financial details, ID cards and private chats.

Justice Minister Katarina Barley described the incident as a "serious attack."

"The perpetrators wanted to damage our trust in democracy and our institutions," she told reporters.

Interior Minister Horst Seehofer said an initial analysis suggests that the material was obtained from cloud services, email accounts or social networks.

Chancellery data leaked

Among the apparent targets were Chancellor Angela Merkel and President Frank-Walter Steinmeier.

"With regard to the Chancellery it seems that, judging by the initial review, no sensitive information and data have been published and this includes (from) the chancellor," a government spokeswoman told reporters.

The hackers published Merkel's fax number, email address and several letters written by and addressed to her, according to the DPA news agency.

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Social Democrat parliamentarian Helge Lindh was one of the victims of the attack. He told DW that although the hack was "alarming," he was not surprised it happened.

"There is evidence of a number of phishing attacks and data leaks collected over a sustained period of time," he said. "It is shocking that politicians are so vulnerable, and it is our task to improve security."

Info leak as early as December

The document leak was first discovered Thursday evening, the RBB Inforadio, a Berlin-area German public broadcaster, reported. However, the documents had apparently been posted online as early as December 2018 over a Hamburg-based Twitter account that released them in an Advent calendar style. The Twitter account describes itself with labels such as security research, artist and satire.

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The Hamburg Data Protection Agency said the Twitter account has been deleted. The agency was working with Irish data protection authorities to prevent the further dissemination of politicians' information.

The authenticity of the leaked data could not be immediately verified and no discernible pattern could be detected to the leaked documents. There is no known suspect or motivation at present.

On Friday, Germany's defense ministry announced they were not affected by the alleged hacking.

According to Reuters, the BSI was only informed about the hacking shortly before the story was reported by German media.

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