The speaker of the German Parliament is planning to approve a criminal investigation into the leak of confidential documents relating to U.S. intelligence activities in the country.

The documents, posted online Thursday by WikiLeaks, came from a parliamentary committee's inquiry into the relationship between German authorities and the National Security Agency.

The inquiry was launched a year after former NSA contractor Edward Snowden revealed details of secret U.S. eavesdropping programs in 2013.

Parliamentary officials Friday confirmed German media reports that Speaker Norbert Lammert would give prosecutors permission to investigate the leak of some 90 gigabytes of data.

Patrick Sensburg, who chairs the panel and is a member of Chancellor Angela Merkel's party, was quoted by Funke Media Group as saying that a "foreign hacking attack can't be ruled out."