When did Israel first hear about Syria's nuclear reactor?

IDF presents timeline showing when Israel first heard about Syria's reactor, up until the decision was made to destroy it.

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Syria's nuclear reactor after the Israeli strike
Syria's nuclear reactor after the Israeli strike
IDF spokesperson

For two years, the Military Intelligence Directorate worked with the Israeli intelligence community to collect information about the growing Syrian nuclear facility.

It began with a hunch and a collection of sensitive information, continued with the recognition of suspicious buildings, and ended with the identification and destruction of the nuclear facility. Here is the intelligence process behind the operation, step-by-step:

After major discoveries were made from 2005 until the beginning of 2007, it was determined that Syria was acting secretly within the nuclear field.

The Military Intelligence Directorate began to take on the challenge: the Research Department of the Directorate established a large-scale team to analyze indications of Syrian nuclear efforts and strategies. Later on, the intelligence collection units outside of the military assisted in gathering information.

During this period of time, the Military Intelligence Directorate collected a number of key details that became the grounds for the attack.

Towards the end of 2004: Military intelligence and the Mossad collected information that foreign specialists were aiding a nuclear project in Syria.

January 2006: This was the first time it was suggested that a nuclear facility was being established in Syria. This was an important turning point in the understanding of it. Following this, the Military Intelligence Directorate collected vital information regarding the beginning process of a nuclear facility.

April 2006: A nuclear facility was identified as a result of research conducted by the Military Intelligence Directorate and intelligence community.

November 2006: Additional activity in the nuclear field was observed. With time, more aspects of Syrian nuclear efforts were revealed, specifically intensive contact with nuclear elements necessary for the operation of a nuclear facility.

From the start of 2007 to September of that year, the Military Intelligence Directorate and the Mossad strengthened intelligence collection by gathering groundbreaking intel in order to prove that their information was pointing towards a nuclear facility.

The information confirmed the leads were correct and that there was one. From here, it was understood that that the Syrian nuclear project was advancing rapidly, and that all security forces - the Mossad, the IAF, and the Military Intelligence Directorate, had to unite for one common operation.

The unified team succeeded in, among other things, directing a large-scale intelligence operation, which included an accurate estimation of the Syrian nuclear project advancement, a system analysis that provided tactical and strategic intelligence, thereby enabling the aerial attack, and finally, organizing the timing of the strike.