In late 2021, Microsoft CEO Satya Nadella met with Yossi Sariel, the commander of "Israel’s" military surveillance agency Unit 8200, at Microsoft’s Seattle headquarters. Sariel sought support for a plan to move vast amounts of classified intelligence data into Microsoft’s Azure cloud platform. This arrangement would provide Unit 8200 with a dedicated, customized space within Azure, offering nearly unlimited storage capacity.

Equipped with Azure’s immense storage capabilities, Unit 8200 developed a sweeping surveillance system that records and stores millions of mobile phone calls made daily by Palestinians in Gaza and the occupied West Bank. This cloud-based system, operational since 2022, allows the agency to retain a vast archive of calls over extended periods.

Microsoft has claimed that Nadella was unaware of the specific nature of the data being stored. However, leaked documents and interviews with 11 sources from Microsoft and Israeli military intelligence reveal that Azure has been central to storing this expansive trove of Palestinian communications.

According to three Unit 8200 insiders, the Azure cloud platform has been instrumental in preparing deadly airstrikes and shaping military operations in both Gaza and the West Bank. While "Israel" has long intercepted calls in the occupied territories thanks to its control over Palestinian telecommunications, the new system indiscriminately records calls from a far larger group of ordinary civilians.

'A million call an hour'

One intelligence source explained that Unit 8200 turned to Microsoft after realizing its own servers lacked the storage capacity and computing power needed to handle the sheer volume of phone calls,  a volume captured by the unit’s internal mantra: “A million calls an hour.”

The surveillance system was designed to run on Microsoft’s servers, protected by enhanced security layers developed jointly by Microsoft engineers and Unit 8200 according to the unit’s specifications. Leaked Microsoft files indicate that much of this sensitive Israeli military data now resides in company data centers located in the Netherlands and Ireland.

Employees, investors concerned about ties to 'Israel’s' military

This revelation about Microsoft’s Azure platform’s role in the surveillance effort emerges amid increasing pressure on the tech giant from employees and investors concerned about its ties to "Israel’s" military and how its technology has been deployed during the 22-month genocide in Gaza.

In May, a Microsoft employee protested during CEO Satya Nadella’s keynote speech by shouting, “How about you show how Israeli war crimes are powered by Azure?” This public outcry followed earlier revelations in January by The Guardian and others about "Israel’s" reliance on Microsoft technology during the Gaza genocide.

In response, Microsoft commissioned an external review of its relationship with the Israeli military. The company stated the review “found no evidence to date” that Azure or its AI tools were “used to target or harm people” in the territory.

A senior Microsoft source said the company had discussions with Israeli security officials, specifying how its technology should be used in Gaza, emphasizing that Microsoft systems must not be involved in identifying "targets" for lethal strikes.

Despite Microsoft’s assurances, sources from Unit 8200 revealed that intelligence gathered from the vast archive of phone calls stored in Azure has been used to identify bombing "targets" in Gaza. One source explained that when planning an airstrike in densely populated areas, officers would use the cloud system to review calls made by people nearby.

Use of the system reportedly increased during the ongoing genocide in Gaza, which has resulted in the killing of over 60,000 Palestinians, including more than 18,000 children.

Arrests without excuse made feasible

Originally, the system focused on the West Bank, home to about 3 million Palestinians under Israeli military occupation. According to Unit 8200 sources, the information held in Azure formed a rich intelligence repository used to blackmail individuals, justify detention, or even killings after the fact.

“When they need to arrest someone and there isn’t a good enough reason to do so, that’s where they find the excuse,” said one source, referring to the cloud-stored data.

Microsoft claimed it had “no information” regarding the specific data Unit 8200 stored in its cloud. The company alleged that its “engagement with Unit 8200 has been based on strengthening cybersecurity and protecting Israel from nation-state and terrorist cyber-attacks.”

They added, “At no time during this engagement has Microsoft been aware of the surveillance of civilians or collection of their cellphone conversations using Microsoft’s services, including through the external review it commissioned.”

‘Tracking everyone, all the time’

The driving force behind this cloud surveillance initiative was Yossi Sariel, the commander of Unit 8200 from early 2021 to late 2024. Described by one insider as a “revolution” within the unit, Sariel was a career intelligence officer who strongly championed large-scale projects like this.

Sariel expanded the scope of communications interception by Unit 8200. His strategy was to begin “tracking everyone, all the time,” said an officer who worked under him.

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'The entire public was our enemy'

Moving beyond targeted surveillance, Sariel’s approach employed mass surveillance across the occupied West Bank, combined with innovative AI tools to extract actionable insights. One source said, “Suddenly the entire public was our enemy,” reflecting how the project aimed to predict which individuals posed security threats.

Among the tools developed during this time was a system that scanned all text messages between Palestinians in the West Bank, automatically assigning risk scores based on suspicious keywords. Known as “noisy message”, it remains in use and can detect texts discussing weapons or expressing a desire to die.

When Sariel became Unit 8200 commander in early 2021, he prioritized building a partnership with Microsoft that would allow the unit to extend its capabilities and capture the content of millions of phone calls daily.

Storing Palestinian phone calls dubbed 'sensitive workloads'

At his meeting with Satya Nadella later that year, Sariel didn’t explicitly mention plans to store Palestinian phone calls in the cloud, instead referring to “sensitive workloads” containing secret data, according to internal meeting records.

However, documents indicate that Microsoft engineers understood the data would include raw intelligence like audio files. Some Microsoft staff based in "Israel", including former Unit 8200 members, seemed aware of the project’s goals. As one source said, “You don’t have to be a genius to figure it out. You tell [Microsoft] we don’t have any more space on the servers, that it’s audio files. It’s pretty clear what it is.”

Microsoft’s spokesperson maintained, “We are not aware of Azure being used for the storage of such data,” stressing that Unit 8200 was a customer of cloud services and that Microsoft “did not build or consult with Unit 8200” on a surveillance system.

Still, in early 2022, Microsoft and Unit 8200 engineers collaborated closely to develop advanced security measures in Azure to meet the unit’s standards. One document described the collaboration’s “rhythm of interaction” as “daily, top down and bottom up.”

 Secrecy, scale of data storage

Within Microsoft, the project was highly secretive, with engineers instructed not to mention Unit 8200 by name. Under the plan, vast amounts of raw intelligence material would be stored in Microsoft data centers overseas.

Files indicate that by July 2025, approximately 11,500 terabytes of Israeli military data, equivalent to around 200 million hours of audio, will be held on Microsoft’s Azure servers in the Netherlands, with a smaller portion stored in Ireland. It’s unclear whether all this data belonged to Unit 8200, as some might belong to other Israeli military units.

According to the documents, Unit 8200 informed Microsoft that it intended to eventually migrate over 70% of its data, including secret and top-secret information, to Azure. The unit was “willing to ‘push the envelope’ with the kind of sensitive and classified information that intelligence agencies normally held on their own servers.” As one executive noted, “They’re always trying to challenge the status quo.”

When asked about Sariel’s meeting with Nadella, Microsoft’s spokesperson said it “is not accurate” to claim that the CEO personally supported the project. They said Nadella “attended for 10 minutes at the end of the meeting” and that there was “no discussion” of the specific data planned for Azure.

However, internal Microsoft records viewed by The Guardian show Nadella expressed support for Sariel’s ambition to transfer a large portion of Unit 8200’s data to the cloud, described earlier in the meeting as “sensitive intelligence material.”

One record states, “Satya suggested that we identify certain workloads to begin with and then gradually move towards the 70% mark.” It adds that Nadella said, “building the partnership is so critical” and “Microsoft is committed to providing resources to support.”

Sariel’s vision, AI advocacy

Several months before his meeting with Microsoft CEO Satya Nadella in 2021, Yossi Sariel published a book on artificial intelligence under a pen name, later revealed by The Guardian to be his own, in which he urged militaries and intelligence agencies to “migrate to the cloud.”

Known within Israeli intelligence as a technology evangelist, Sariel prized what he described to colleagues as a friendly relationship with Nadella. A senior intelligence source said, “Yossi bragged a lot, even to me, about his connection with Satya.” (Microsoft has denied that Nadella and Sariel had a close relationship.)

Another former intelligence colleague added, “He sold [the partnership] internally and got a huge budget. He claimed it was the solution to our problems in the Palestinian arena.”

Sariel declined to comment and referred questions about the project to the Israeli occupation forces (IOF). An IOF spokesperson claimed that their cooperation with companies like Microsoft was based on “legally supervised agreements.” The spokesperson alleged, “The IDF operates in accordance with international law, with the aim of countering terrorism and ensuring the security of the state and its citizens.”

Microsoft’s commercial interests, protests

For Microsoft, the multi-year collaboration with Unit 8200 represented a significant commercial opportunity. Executives anticipated earning hundreds of millions of dollars in revenue and described the partnership as “an incredibly powerful brand moment” for their Azure cloud platform, according to leaked files.

One executive noted that Unit 8200’s “leadership hopes to expand the mission-critical work tenfold in the coming years.”

As Unit 8200 began utilizing Azure’s storage capabilities in 2022, intelligence officers quickly realized the scale of the new tool’s potential. One source familiar with the system described it simply: “The cloud is infinite storage.”

Calls stored in the system, including those made by Palestinians to Israeli and international numbers, are generally kept for about one month, although the storage capacity can be extended to hold calls for longer periods when necessary. Several intelligence sources explained that this allows officers to retrieve past phone conversations of persons who later become of interest. Previously, surveillance targets had to be pre-selected for their calls to be intercepted and stored.

However, the system notably failed to stop Operation Al-Aqsa Flood.

Following October 7, Sariel faced criticism for prioritizing “addictive and exciting” technology over traditional intelligence methods. Critics argued this focus contributed to the intelligence failure. Sariel resigned the following year, acknowledging “8200’s part in the intelligence and operational failure.”

Use of AI tools and Gaza genocide impact

During the subsequent genocide war, the cloud system Sariel developed has been frequently used alongside new AI-driven target recommendation tools that were also introduced under his leadership. These technologies have played a key role in military operations that have caused widespread devastation and a severe humanitarian crisis for civilians.

While "Israel’s" destruction of Gaza’s telecommunications infrastructure has decreased the volume of phone calls, sources say the data stored in the cloud remains valuable. One source noted that intelligence officers working on Gaza have become increasingly enthusiastic about the system as the conflict continues, believing the military is “heading towards long-term control there.” 

Broader implications

The expansive surveillance program reveals how technology firms like Microsoft can become deeply entangled in complex geopolitical conflicts. Despite Microsoft’s claims that its technology is not used to target Palestinians or support lethal strikes, internal sources and leaked documents paint a different picture of extensive intelligence gathering on Palestinians.

As protests grow and employees voice concerns, with one shouting during a keynote, “How about you show how Israeli war crimes are powered by Azure?,” the debate intensifies over the ethical responsibilities of tech companies working with military and intelligence agencies.

The case of Unit 8200 and Microsoft illustrates the immense power and risks of cloud technology, raising urgent questions about privacy, accountability, and the future of surveillance in war zones.