Israel convened an emergency Diplomatic-Security Cabinet meeting on Tuesday to discuss the transfer of Russian S-300 missiles to Syria.
The meeting took place ahead of Prime Minister Benjamin Netanyahu's departure to the U.N. General Assembly in New York, where he is expected to bring up Israeli-Russian tensions in a meeting with U.S. President Donald Trump.
Moscow announced its plans to deliver up to eight S-300 batteries to Syria on Monday, citing last week's downing of a Russian reconnaissance plane by Syrian forces, which mistook the Russian aircraft for an Israeli fighter jet. Fifteen Russian crewmen were killed in the incident, stoking regional tensions.
Russia laid the blame entirely on Israel, saying Israeli fighter jets were hiding behind the Russian plane, an account denied by the Israeli military.
Netanyahu spoke with Russian President Vladimir Putin on Monday about the issue.
A statement by the Prime Minister's Office said that Netanyahu warned Putin that supplying advanced weapons systems to Syria would only intensify tensions in the highly volatile region.
"The prime minister expressed his confidence in the credibility of the IDF's investigation [into the incident] and its conclusions, and reiterated that the Syrian military, which shot down the plane, and Iran, whose aggression is undermining stability, are responsible for the unfortunate incident," the statement said.
"Prime Minister Netanyahu said that transferring advanced weapons systems into irresponsible hands will ramp up the dangers in the region, and added that Israel will continue to defend its security and its interests. It was also agreed to continue the dialogue between the professional teams and the inter-military coordination via the military channels."
Former Military Intelligence Director Maj. Gen. (ret.) Amos Yadlin tweeted that the Russian accusations that Israel was to blame for the Russian plane being shot down were "fake news" meant "to amplify diplomatic pressure and deflect responsibility from Syrian and Russian officers for downing the plane."
Yadlin tweeted, "Supplying S-300 missiles [to Syria] increases the risk posed by unprofessional Syrian operators first and foremost to the Russian Air Force, to Israel, the United States and the coalition as well as to civil aviation.
"Israel has been preparing for this threat for 20 years and will know how to handle it."
Israel has long lobbied Russia not to provide Syria with S-300 missiles, fearing this would hinder Israel's aerial ability to strike Iranian and Hezbollah assets in Syria.
Russian Defense Minister Sergei Shoigu said Moscow had in the past obliged Israel, but last week's incident had forced Moscow to take "adequate retaliatory measures" to keep its troops safe.
Kremlin spokesman Dmitry Peskov said the decision to supply the weapons was not directed at any third country.
"Russia needs to increase the safety of its military and it should be clear for everyone," he said.
But he also repeated Moscow's accusations that Israel was to blame for the plane's downing, saying, "No doubt that according to our military experts, deliberate action by Israeli pilots was the reason for the tragedy and this cannot but harm [Russian-Israeli] ties."
Russian news website Kommersant reported Tuesday that Russia plans to supply Syria with at least two S-300 air defense missile systems within the next two weeks. The systems will be deployed along Syria's coast and later on its borders with Jordan, Israel, Lebanon and Iraq.
Russian news outlet Izvestia reported that Moscow is boosting its electronic warfare systems in Syria as well, saying the first systems have already been delivered to the Hmeimim air base in Latakia, to be used by Russian forces stationed there.
In the U.S., the White House expressed concern at the Russian plans to supply the S-300 surface-to-air missile system to Syria, saying it hoped Russia would reconsider the move.
U.S. Secretary of State Mike Pompeo said he would discuss the issue with Russian Foreign Minister Sergey Lavrov in New York. The two are scheduled to meet on the sidelines of the U.N. General Assembly this week.
"We are trying to find every place we can where there is common ground, where we can work with the Russians," he said. He added that Russia was working against the United States in many areas, and "we will hold them accountable."
U.S. National Security Adviser John Bolton said Monday that the delivery would cause a "significant escalation" in already high regional tensions.
"There shouldn't be any misunderstanding here – the party responsible for the attacks in Syria and Lebanon and really the party responsible for the shooting down of the Russian plane is Iran," he said.
Bolton said a political process is needed to end Syria's war but that Russia's plans with the S-300 are making that difficult.
He said U.S. troops would stay active in Syria as long as Iran was involved.
"We're not going to leave as long as Iranian troops are outside Iranian borders, and that includes Iranian proxies and militias," he said.
"We think introducing the S-300s to the Syrian government would be a significant escalation by the Russians and something that we hope, if these press reports are accurate, they would reconsider."
Russia's Deputy Foreign Ministry Sergei Ryabkov responded to Bolton's comments by warning the U.S. against taking "a mentor's tone."
International and regional powers backing various sides in Syria's civil war have been carrying out strikes for years, often using special hotlines to prevent aerial confrontations.
Russian officials said Syria's Soviet-made S-200 systems, one of which downed the Russian plane, were not sophisticated enough to identify the Russian aircraft as a friendly one.
Originally developed by the Soviet military, the S-300 fires missiles from trucks and is designed to shoot down military aircraft and short- and medium-range ballistic missiles.
Alexander Khramchikhin of the Moscow-based Institute of Military and Political Analysis said the S-300 could "seriously affect Israel's ability to carry out its strikes in Syria."
Dmitri Trenin, director of the Carnegie Moscow Center and a former colonel in the Russian army, said the S-300 would make Israel "more careful in the vicinity of Russian assets."
Syrian President Bashar Assad's office issued a statement saying, "President Putin held Israel responsible for bringing down the plane and informed President Assad that Russia will develop Syria's air defense systems."
