Prime Minister Benjamin Netanyahu has met Russian leader Vladimir Putin in Moscow to discuss ways of avoiding any unintended clashes in Syria between Israel and Russian forces supporting President Bashar al-Assad.

Emphasising the importance of the visit, Mr Netanyahu took along with him the chief of Israel's armed forces and the general in charge of Israeli military intelligence.

A rapid Russian build-up in Syria, which regional sources have said includes warplanes and anti-aircraft systems, worries Israel, whose jets have on occasion bombed the neighbouring Arab country to foil suspected handovers of advanced arms to Assad's Lebanese guerrilla allies Hezbollah.

Ahead of Mr Netanyahu's meeting with Putin, a former adviser to the Israeli leader said he would try to work out "ground rules" for keeping the countries' forces from accidentally trading fire.

"I'm here because of the difficult security situation, which is becoming increasingly complex on our northern border," Mr Netanyahu told Mr Putin in the Russian president's residence of Novo-Ogaryovo outside Moscow.

He told Mr Putin he was in Russia to prevent "confusion between your forces and our forces in the region".

A US official told Reuters US-Israeli coordination allowed the allies to share classified technologies for identifiying Russian aircraft over Syria: "We know how to spot them clearly and quickly," the official said.

The US, which along with its allies has been flying missions against Islamic State insurgents in Syria, has also been holding so-called "deconfliction" talks with Russia.

Mr Netanyahu said on his Facebook page he had told Putin about Israel's policy of striking at suspected threats from the Syrian Golan. He added: "Given these circumstances, I came to Russia, to make clear our policy and also to enable that there be no misunderstanding between our forces."

Mr Putin said Russia's actions in the Middle East would always be "responsible".

Two US officials said Russia had started flying surveillance missions with drone aircraft in Syria in what appeared to be Moscow's first air operations in Syria since beginning its build-up. Israel is also concerned top-of-the-line Russian military hardware now being deployed could benefit Hezbollah and one day be turned against the Jewish state.

"Our policy is to do everything to stop weapons from being sent to Hezbollah," Mr Netanyahu said.