Israel President Reuven Rivlin takes part in a wreath-laying ceremony Wednesday at the Tomb of the Unknown Soldier at the Kremlin wall in Moscow. (Maxim Shipenkov/AP)

Israel viewed Russian President Vladimir Putin’s announcement that he was removing the bulk of his troops from Syria with a mix of surprise and concern.

Israeli President Reuven Rivlin met with Putin in Moscow on Wednesday as part of a visit to mark 25 years of diplomatic ties between the two countries.

During the meeting, which lasted two hours, Putin reiterated Russia’s commitment to Israel’s security, a senior adviser to Rivlin said, speaking on the condition of anonymity because he was not authorized to brief the news media.

He said Rivlin made clear Israel’s concerns regarding the wider regional instability and stressed issues that would constitute red lines in terms of Israel’s security.

Israeli journalists traveling with Rivlin reported that he spoke to Putin about the possibility of U.N. peacekeeping troops returning to the tense border between Syria and the Israeli-controlled portion of the Golan Heights. It was also reported that Prime Minister Benjamin Netanyahu might soon be heading to Moscow to meet with Putin.

Russian President Vladimir Putin announced Russia will begin pulling most of its military from Syria. (The Washington Post)

[Putin announces Russia will pull most of its military from Syria]

Israelis, like others closely monitoring the conflict, had little understanding of what had driven the Russians to pull back from the fight. But for Israel, which borders Syria on its northern edge, there was fear that a vacuum in the war-torn country could allow Israel’s enemies — Iran and its Lebanese proxy, the Shiite militia Hezbollah — to gain strength.

Israel not only is anxious about spillover of fighting in southern Syria into the Golan Heights but is also worried about transfers of Iranian and Syrian missiles and weapons to Hezbollah.

“Everybody understands that the Islamic State is a danger to the entire world, but for us, fundamentalist Iranian Shiite Islam is no less of a danger,” Rivlin said as he left for Russia on Tuesday evening.

Rivlin is the first foreign leader to meet with Putin since he announced the withdrawal from Syria.

Speaking in the Knesset on Tuesday, the Israeli army’s chief of staff, Lt. Gen. Gadi Eisenkot, said Israeli officials had not received any information in advance about Putin’s plans to pull out and were as surprised as everyone else. He said it was likely that the Russians would reduce their presence in a gradual manner, maintaining a naval and air base in Syria.

Although Israel has refrained from direct involvement in the five-year-old Syrian conflict, it has been keeping a close eye on the situation there.

Russian President Vladimir Putin, right, and Israeli President Reuven Rivlin meet in the Kremlin. (Maxim Shipenkov/AP)

Along the demilitarized zone on the Golan Heights, groups for and against Syrian President Bashar al-Assad vie for control. Additionally, fighting between rebels and Assad forces often spills over into Israel, with stray rockets or wounded fighters crossing the border.

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Moshe Marzuk, a researcher at the International Institute for Counter-Terrorism in Herzliya and former head of the Israeli army’s Lebanon and Palestinian intelligence division, said there is real concern that Hezbollah has gained strength and valuable military experience from its involvement the Syrian conflict. Hezbollah fought an intense three-week war with Israel in the summer of 2006.

“I don’t think Hezbollah will try to do something to Israel at this stage — it knows it will pay an expensive price if it does,” he said. “But Israel still has to keep monitoring the situation closely.”

Marzuk said that although the Russians were physically pulling out, they still had a vested interest in the region and in helping to bring stability to Syria.

Yaakov Amidror, a former major general in Israel’s army and former national security adviser, played down the threat to Israel that might arise from Russia’s move.

“I think there will be the same vacuum as there was before the Russians entered,” he said. “We have been living with this situation for a long a time, and just like there was not any real change when the Russians came in, there will not be any real change now that they are leaving.”

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