Moscow (CNN) Russia will upgrade Syria's air defense system after a series of statements over the past week chastising Israel for the downing of a Russian aircraft.

The move, announced by the Russian Defense Ministry on Monday, has drawn criticism from Israel, which regularly conducts airstrikes in Syria against what it says are Iranian targets. In a tweet Monday, United States National Security Adviser John Bolton called the Syrian government's purchase of Russia's S-300 air defense missiles "a significant escalation."

Russia's Defense Ministry has said the system would be transferred to Syria in the next two weeks.

The ministry said that Israel was "solely" to blame for bringing down the IL-20 aircraft last week. The plane was inadvertently shot down by Syrian forces during an Israeli airstrike in the Syrian coastal province of Latakia. Russia's military accused Israel of maneuvering its aircraft to use a Russian plane "as cover," putting it in the line of fire of Syria's antiaircraft system.

Russia's military also said that Israel provided misleading information about the airstrike over a military hotline. The two countries follow a de-confliction mechanism, keeping each other informed about their military actions in the country.

Israel's military denied the accusations and said it followed established protocols in communicating with Moscow, presenting full information about the incident to Russia in an after-action review. In a phone call with Russian President Vladimir Putin, Israeli Prime Minister Benjamin Netanyahu held the Syrian government and its Iranian allies responsible for downing the Russian plane.

"Transferring advanced weapons systems into irresponsible hands will increase the dangers in the region," Netanyahu said during the phone call in response to the announcement. He added that Israel "will continue to defend its security and its interests."

But Russia has argued that it had previously withheld the advanced military hardware from Damascus as a favor to Israel. The downing of the plane prompted Moscow to reverse the decision, according to Russia's defense minister.

"In 2013, at the request of the Israeli side, we suspended the delivery of the S-300 complex to Syria which was prepared to receive delivery and for which Syrian military personnel were trained," said Russian Defense Minister Sergei Shoigu on Monday.

"Today the situation has changed. And it is not our fault."

Making Israeli airstrikes more difficult

Russia has argued that its deployment of the S-300 system would boost the security of its contingent in Syria. The improved radar system enables Syrian surface-to-air missiles to better discern targets and helps prevent the accidental shooting down of Russian planes.

But the new system potentially makes Israeli airstrikes in Syria more difficult. The missile range of the S-300 is around 250 kilometers, allowing defense systems that are set to be positioned in the northern Syrian coastal province of Latakia to cover Israel's northern territories.

Russia's military operates a major airbase in Latakia province, the same region where Israel conducted last week's airstrike.

The Russian military also says it will jam communications and Global Positioning Systems (GPS) over the Mediterranean Sea, which Israeli planes often fly over for their bombing runs.

Russia has served as a power broker in Syria's conflict, intervening on behalf of the Syrian government against rebel fighters while trying to ease Israel's security fears in the country. Last month, Russia said it convinced its Iranian allies to withdraw to at least 85 kilometers away from the Israeli border, relieving Israel of a major security concern.

Russian President Vladimir Putin shakes hands with his Syrian counterpart Bashar al-Assad during a meeting in Sochi on May 17, 2018.

"This is an extremely ungrateful response to all that Russia has done for Israel and the Israeli people recently," Russian Defense Ministry spokesman Major General Igor Konashenkov said on Sunday according to Russia's official TASS news agency.

"The Israeli military command either does not value the current level of relations with Russia or does not control certain military units," Konashenkov said. He said that during the September 17 attack, Israeli jets approached the Russian IL-20 aircraft as it was preparing to land."The Syrian air defenses must have taken that maneuver for a new attack by the Israeli air force," he said.

"The Israeli fighter jets used the Russian II-20 aircraft as cover against missiles and continued their maneuvers in the area," he added. The Russian military also released an animation on its social media pages to illustrate its version of events.

Putin discussed the weapons system delivery with Syrian President Bashar al-Assad on Monday, according to a Kremlin statement. The Russian leader has refrained from pointing fingers at the Israelis, departing from the rhetoric of the Defense Ministry. Last Tuesday, Putin called the incident part of "a chain of tragic accidental circumstances, because Israel didn't shoot our plane down."