BERLIN (Reuters) – Germany’s government was marshalling its defenses on Thursday against a powerful cyber attack that lawmakers said had breached the foreign ministry’s computer network and whose origins officials admitted were still unclear.

The head of a parliamentary oversight panel said the attack was continuing, and security officials were trying to maintain control.

“It is a veritable cyber attack on parts of the government network,” conservative lawmaker Armin Schuster told reporters. “It is a continuing process.”

Schuster declined to give further details, saying that would provide a warning to the attackers, who he did not identify.

“The loss of sensitive information amounts to significant damage on its own,” Schuster said. “But we can say that the German government is trying, as far as we know today, to keep the process under control.”

Facing criticism from lawmakers that they were kept in the dark about the attack, which security officials said they learned of some time ago but authorities first confirmed on Wednesday, Interior Minister Thomas de Maiziere said the hack was technically sophisticated and planned long in advance.

He said security authorities were trying to gain further insight into how it was carried out.

Source: German government under cyber attack, shores up defenses