Russia cannot compel Iranian forces to quit Syria, Moscow's ambassador to Tel Aviv said on Monday, rebuffing Israel's long-standing demand that it should work to ensure their total withdrawal from the country.

Ambassador Anatoly Viktorov said Moscow could equally do nothing to prevent Israeli military strikes against Iranian forces in Syria. Russia is a key backer of Bashar Assad's regime alongside Iran and Lebanon's Hezbollah, two sworn enemies of Israel.

"The Iranians are playing a very, very important role in our common efforts to eliminate the terrorists in Syria," Anatoly Viktorov said in English-language comments on Israel's private Channel 10 broadcaster, as reported by Agence France-Presse (AFP).

"That's why, for this period of time, we see as non-realistic demands to expel any foreign troops from the territory of the Syrian Arab Republic," he said. Anatoly said Iran's presence in Syria was "fully legitimate according to U.N. principles."

With Assad now in almost complete control of southwestern areas abutting the Israeli-occupied sector of the Golan Heights, Russia had offered to keep Iranian forces at least 100 km (60 miles) from the Golan Heights cease-fire line. The offer came up during a meeting between Israeli Prime Minister Benjamin Netanyahu and visiting Russian Foreign Minister Sergei Lavrov, but Israel rejected it as insufficient, the official said.

Israel seized 1,200 square kilometers (460 square miles) of the Golan from Syria in the Six-Day War of 1967 and later annexed it in a move never recognized by the international community. Israel opposes Assad but has sought to avoid being dragged into the Syria's civil war. However, it has carried out strikes to stop arms deliveries to the Lebanese militia Hezbollah, which fights alongside Assad's forces. Israel fought a war against Hezbollah in 2006.

While formally neutral in the seven-year-old civil war next door, Israel has carried out scores of air strikes against suspected emplacements or arms transfers by Iranian or Lebanese Hezbollah guerrillas in Syria, apparently unimpeded by the Russian defense systems deployed there. A military hotline Israel and Russia set up in 2015 has also helped the countries avoid inadvertently clashing over Syria.

Since the war broke out, Israel has supported Bashar Assad's removal and made warnings about the advancement of Iran and its proxies. Israel wants Assad to leave the post and Iran to stop supporting Shiite militants. Iran has helped the Assad regime throughout the war, dispatching thousands of soldiers, mobilizing the Hezbollah group and delivering millions of dollars, despite its troubled economy, suffering due to international sanctions.