German Chancellor Angela Merkel announced on Monday that her office would be willing to cooperate with a parliamentary investigation into the accusations of misconduct.

According to the latest allegations, published in "Der Spiegel" news magazine on Saturday, Germany's foreign intelligence service, the BND, helped the NSA to conduct surveillance on German officials and firms.

This includes German arms manufacturers and companies such as Airbus.

Merkel also stated she still believed that friendly nations should not spy on each other, referring to 2013's revelations.

Almost two years ago it was revealed that US intelligence services had been tapping Merkel's phone, straining the relationship between the two countries.

Merkel said the BND's first priority was to ensure the safety of German citizens.

"This ability to carry out its duties in the face of international terrorism threats is done in cooperation with other intelligence agencies - and that includes, first and foremost, the NSA," she said.

Earlier in the day, politicians from both sides of the political spectrum called on the chancellor to disclose what she knew about the accusations, with The Left's Gregor Gysi demanding she testify before the special committee heading the investigation.

Interior Minister Thomas de Maiziere is scheduled to appear before the government's intelligence committee on Wednesday.

German Economy Minister Sigmar Gabriel, a member of the Social Democrats, said he has spoken to Chancellor Merkel about the scandal on two occasions, and both times she has assured him there is no evidence to suggest widespread industrial espionage.

"I have no doubt that the Chancellor has accurately responded to my question," he said.

an/jil (dpa, Reuters, AFP)