The two main fighting camps in Syria are Turkey and the Arabs of the Persian Gulf on one side, the Sunni bloc, and the Iranians and the Iraqis on the other, the Shiite block. The majority of the Syrian Arabs are Sunni Muslims, but the Syrian dictator Bashar al Assad, the son of the previous Syrian dictator Hafez al Assad, is an Alawite Muslim, and a traditional Russian and Iranian ally. Alawites are an off-shoot of Shiite Islam.
In 2009 Assad did not allow the Qatar-Turkey pipeline to pass through Syria, while in 2010 he accepted the Iran-Iraq-Syria pipeline which would be constructed by Gazprom, and as a result the Turks and the Arabs of the Gulf attacked Syria. With the exception of the Shiite Iraq of course, which has allied with Iran even though the Iraqis are Arabs and not Persians like the Iranians. See “Who is Responsible for the War”.
The Americans should be on the side of the Turks and the Saudis, and the Russians should be on the side of the Iranians and the Syrians, even though things became a lot more complicated after the improvement in the relations between the Americans and the Iranians, and the agreement about Iran’s nuclear program. However we still see Russia supporting Assad. Actually after the recent tensions between Russia and Turkey the Russians decided to increase their support of Assad. See “From Dagestan to Syria”.
The Russians have decided to send more Russian units to Syria, probably scared about a Turkish move. The extra support also inclueds advanced anti-aircraft missiles.
Until now the Israelis have been careful not to be associated with neither party in the Syrian conflict, because if the supported the Assad regime they would cause problems in their relations with the Saudis, with whom they cooperate against the Iranians, and if they supported the anti-Assad forces they would cause problems in their relations with the Russians, with whom they cooperate against the Islamists supported by Turkey and Qatar.
Moreover if the Israelis supported Assad, they would infuriate their enemy Turkey, and if they supported the anti-Assad forces they would infuriate their other enemy Iran. Therefore the Israelis have taken some targets in Syria which were important for their own security, and these targets could be pro-Assad or anti-Assad, and therefore neither side could claim that Israel was not neutral. After all both Assad and ISIS are Israel’s enemies.
However now the Israelis worry that if Russia brings advanced military equipment in Syria, this equipment might also be used against Israel, and the Israelis are afraid of possible Russian-Israeli clashes in Syria, as you can read at the following Haaretz article, titled “Netanyahu Seeks Understanding With Putin to Prevent Israel-Russia Clashes in Syria”, September 2015. Haaretz is a left newspaper and Israel’s oldest newspaper. The Israeli Prime Minister will visit Russia next week to discuss the subject with the Russian Prime Minister Vladimir Putin. That comes after Russia’s decision to sell Iran the advanced S-300 anti-aircraft missiles, which strained ties between Israel and Russia.
It will be very unfortunate for Israel if Russia decides to step up military support for Syria and Iran, because Israel might lose the smooth cooperation it enjoys with Russia against the Islamist groups supported by Qatar and Turkey. Of course Israel cooperates with Russia without ever going against the Americans. They Israelis could not go against the Americans, because if the Americans decided to turn their back on Israel there would be no more Israel.
“Netanyahu Seeks Understanding With Putin to Prevent Israel-Russia Clashes in Syria”, September 2015