If there’s a clear indication that Israel intends to continue bombing Syria despite threats from Iran, this is it.

Israel’s Arutz Sheva radio reported on Monday that the government of Prime Minister Benjamin Netanyahu had sent a clear message to Russia that it must not sell its advanced S-300 air defense system to the Syrian regime.

This after Moscow had reportedly been reconsidering its decision not to sell the S-300 to Damascus following a joint US-British-French air raid on Syria over the weekend.

Russia is trying to help Syrian dictator Bashar Assad stay in power, and Israeli, US and other Western air strikes have primarily targeted forces loyal to his regime and those of his Iranian and Hezbollah allies.

Israel’s warning to Russia, and the possibility that Russia will anyway supply Syria with advanced air defenses, has heightened concerns that the region, and perhaps the world, is on the brink of a major all-out war.