Hackers carried out a major attack on Germany's center-right Christian Democratic Union (CDU), the federal interior ministry confirmed, quoted by DPA and BTA.
The agency did not disclose details of the scale or nature of the attack, which is being investigated by the Office for the Protection of the Constitution, Germany's counterintelligence agency.
"However, what we can say is that it was carried out extremely professionally," said a spokesman for the Ministry.
The case is being taken very seriously, sources close to the government said.