Data and documents belonging to hundreds of German politicians have been hacked and posted online via Twitter.

Key points: The far-right Alternative fur Deutschland (AfD) was the only party not affected by the hack

The far-right Alternative fur Deutschland (AfD) was the only party not affected by the hack However the right-wing party was the target of a bomb blast outside its offices in Saxony

However the right-wing party was the target of a bomb blast outside its offices in Saxony Nobody's owned up to the hack, but police have detained three men over the blast

The data was posted in daily batches before Christmas on a Twitter account that has been active since mid-2017.

It affected politicians from all parties in parliament except the far-right Alternative for Germany (AfD), public broadcaster RBB reported.

Although the data reportedly included personal information such as mobile phone numbers, addresses, internal party communications and in some cases bills and credit card details — some years old — it did not appear to include politically sensitive documents.

Politicians from the far-left Linke party were among those affected, including Dietmar Bartsch, leader of its group in the lower parliamentary house, a spokesperson said.

Local media reported that Chancellor Angela Merkel and President Frank-Walter Steinmeier were also victims of the leaks.

The identity of the hackers and their motive were not known.

Bild newspaper said the secure internal network of Germany's government was not hit by the hackers, citing sources inside the Federal Office for Information Security.

Three men arrested for blast at far-right party's office

The blast set the office on fire and damaged nearby buildings and vehicles. ( Reuters: Matthias Rietschel )

Meanwhile local police detained three men over an explosion at an AfD office in the eastern state of Saxony.

There were no injuries.

The blast set the office, in the city of Doebeln, on fire and damaged vehicles and nearby buildings, Saxony's LKA criminal investigation office said in a statement.

The LKA said its anti-terrorism unit had determined that the explosion was an escalation in politically motivated attacks targeting AfD offices in Saxony, that are usually limited to acts of vandalism.

"The attack against the AfD office in Doebeln is special given that the explosion was intended to harm people," the LKA said.

Saxony was the site of far-right riots and demonstrations sparked by the stabbing to death of a Cuban-German man in the city of Chemnitz in August, initially blamed on two migrants from Iraq and Syria.

While Saxony has been a large home for Germany's far-right, it is also home to many supporters of the hard-left Die Linke, which is the second-largest party in the regional assembly.

Reuters/AP