A top South African official has condemned an alleged leak of South African intelligence documents and says an investigation is underway.

David Mahlobo, South Africa's state security minister, said in a statement Wednesday that any leak of classified information undermines national security.

The Guardian and Al-Jazeera news organizations published the intelligence documents this week after the files were allegedly leaked.

The files document past South African monitoring of suspected Iranian spies as well as communication between South African intelligence and the CIA and Israel's Mossad spy agency.