Germany has confirmed that it has been the target of an ongoing cyberattack on government computer systems.
"It is a real cyberattack on part of the government system. It's an ongoing process, an ongoing attack," said Armin Schuster, a member of Chancellor Angela Merkel's Christian Democrats and chairman of the parliamentary committee on intelligence issues.
The interior ministry's parliamentary state secretary, Ole Schroeder, said necessary security measures were being taken, assuring the attack was "under control".
"We succeeded, through excellent cooperation, to isolate and bring under control a hacker attack on the federal network," he said, adding however that the security measures had "not yet been completed."
News of an attack targeting the German government IT network first broke out on Wednesday in a report by German news agency dpa.
Citing unidentified security sources, dpa claimed that the attack had been launched by Russian hacker group APT28, also known by other names including "Sofacy" and "Fancy Bear".
According to dpa, the attack was uncovered in December and may have been going on for a year.
APT28 is already accused of attacking the German parliament in 2015. Dpa linked it to Russia's GRU military intelligence agency which is accused of meddling in the 2016 US presidential election.
Lawmakers expressed outrage after they first heard of the attacks on government IT servers from the media.
"While there may be good arguments about why some of the information was kept tight during the past weeks, it is completely unacceptable that yesterday afternoon we were informed by dpa," Konstantin von Notz, Greens lawmaker, who is the deputy of the committee, told reporters on Thursday.
"I fear that in the coming weeks quite a bit more will come to light," Left Party lawmaker and intelligence oversight committee member Andre Hahn said.
"If it turns out to be true, it is a form of warfare against Germany," the head of the digital affairs committee, Dieter Janacek from the Greens party, told the Berliner Zeitung newspaper.
He described the attack as "severe" and called on the government to pass on the information it has to parliament.
Top German intelligence officials have urged lawmakers to give them greater legal authority to "hack back" in the event of cyberattacks from foreign powers.
Moscow has previously denied in any way having been involved in cyberattacks on the German political establishment.