Russia has not been able to produce an effective UAV, a weakness exposed during its brief 2008 conflict with Georgia, and it has made no secret of the fact that it wants to reverse-engineer the Israeli craft to fast-track production.
Moscow bought 12 Israeli UAVs under a $53 million deal signed in April with state-owned Israel Aerospace Industries, but not disclosed until June. These comprise IAI's second-tier craft, the Bird-Eye 400 mini-UAV, the I-View MK 150 tactical UAV and the Searcher Mark 2 medium-range UAV.
That was Israel's first sale of military platforms to Russia. It was also Russia's first purchase of a foreign weapons system.
Israeli defense sources say that the new deal under negotiation with IAI involved improved surveillance equipment. IAI declined comment, but one Israeli sources noted: "The Russians are going for a triple upgrade of their fleet and its capabilities."
According to other sources, Russia wants 50 Israeli UAVs, particularly long-endurance craft.
That likely includes IAI's Heron, the largest Israeli surveillance drone with a 54-foot wingspan. It has the ability to stay aloft for 50 hours at a time at an altitude of 30,000 feet. It can also carry missiles and can be refueled in flight from tanker aircraft.
It was Georgia's use of long-endurance Hermes 450 tactical spy drones, built by Israel's Elbit Systems, to provide battlefield reconnaissance in the 2008 fighting that caught Moscow's interest.
The Russians, who had to rely on the less effective Tu-22 strategic bombers for battlefield intelligence, decided to acquire Israeli craft for the purpose of studying them and reproducing them in Russia.
The Russians have been building unmanned aircraft for several decades, but never achieved the degree of success of U.S. and Israeli companies. Their craft have only a fraction of the flight duration of the Israeli UAVs and have long had reliability problems.
Following the Georgia conflict, the Russian air force launched several UAV projects, with the objective of having operational systems by 2011. But Russian defense contractors, including the state-owned Ikut aircraft manufacturer and the Vega Radio Engineering Corp., were unable to come up with systems that met the air force's requirements.
According to various estimates, the Russians need at least 100 UAVs and at least 10 guidance systems to provide the battlefield surveillance the military needs.
In the first UAV sale to Russia in June, the Israelis withheld the most advanced UAV variants after several Russian officials publicly stated that the main reason they wanted the UAVs was to purloin their technology.
But the Israelis understood that it was vital to be able to influence Moscow, Iran's main arms supplier, to block the delivery of S-300PMU air-defense missiles to the Islamic Republic.
It wants the advanced system to protect its nuclear facilities from threatened Israeli airstrikes.
Indeed, in 2008 Gen. Amos Gilad, head of the Israeli Defense Ministry's Diplomatic Security Bureau, visited Moscow and received assurances that Russia would not provide S-300s to Iran or MiG-31 interceptor jets to Syria.
Iranian leaders have been complaining vociferously about Moscow's refusal to honor an $800 million contract for five S-300 batteries signed in 2007 as tension between the United States and Iran swelled once more over Tehran's nuclear program, raising the prospect of unilateral Israeli military action.
Israeli Prime Minister Binyamin Netanyahu secretly flew to Moscow several weeks ago to press President Dmitry Medvedev and Prime Minister Vladimir Putin not to send S-300s to Iran and was reportedly given renewed assurances they would not.
"The UAV sale/technology theft was basically a bribe to ensure that the Russians did not equip Iran with better anti-aircraft missiles," according to one Western analyst.
"Letting Russia steal UAV technology has suddenly become more important than keeping Iran or Syria down."
Notable deaths of 2014 [PHOTOS]