Concerns that tech company’s Israel-based staff may have concealed key details of work follow Guardian investigation

Microsoft is investigating how Israel’s military surveillance agency, Unit 8200, is using its Azure cloud storage platform, amid concerns the company’s staff in Israel may have concealed key details about its work on sensitive military projects.

Senior executives are scrambling to assess what data Unit 8200 holds in Azure after a Guardian investigation revealed how the spy agency has used the cloud platform to store a vast collection of intercepted Palestinian mobile phone calls.

The joint investigation with the Israeli-Palestinian publication +972 Magazine and Hebrew-language outlet Local Call found Unit 8200 has used a customised and segregated area within Azure to store recordings of millions of calls made each day in Gaza and the West Bank.

According to Unit 8200 sources interviewed as part of the investigation, intelligence drawn from the enormous repository of phone calls held in the cloud has been used to research and identify bombing targets in Gaza.