On Tuesday night, US President Donald Trump announced that his country would abandon the nuclear deal with Iran and expressed concern in Tehran that Tehran meant to use the opportunity to attack Syria.
Israeli military officials are attributing the attack to members of the Iranian Revolutionary Guard Corps' Quds Forces.
Israel is concerned that Iran and Hezbollah are embedding forces along its border.
His trip Wednesday came as Syrian state-run media said Israel struck a military outpost near the capital, Damascus, the previous night.
Social media users report that Israeli tanks have fired at positions in Syria, Israeli air sorties have been initiated, and that Syrian artillery is shelling Israeli targets.
North Korea says denuclearization pledge not result of US-led sanctions
The planned summit is being watched closely as it will be the first meeting between sitting leaders of the USA and North Korea. The Rodong Sinmun commentary, however, said that Japan must first shift its stance on maintaining pressure on the North.
Ahead of the meeting, Putin had said he would discuss "problems in the region", saying that "the situation unfortunately is very acute".
The Israeli and Russian militaries have been in contact throughout much of Russia's intervention in Syria, where Moscow has waged an air campaign in support of Assad's forces since 2015.
As Israel's Prime Minister Benjamin Netanyahu welcomed Trump's move to pull out of the nuclear deal - much as he did the president's other unilateral move (to relocate the USA embassy from Tel Aviv to Jerusalem), the country's military signaled that it is on high alert.
Netanyahu's visit to Moscow coincided with Russia's celebration of the anniversary of Nazi Germany's capitulation in World War II. The Syrian Observatory said the casualty number from Tuesday's strike is likely to go up because of a large number of people who were wounded and a number of people who are missing. In December, Israel reportedly bombed military positions in Kissweh, including a weapons depot. The objective is believed to have been a base for Iranian fighters allied with the Syrian government.
There have been fears in Israel of Iranian retaliation.