Russia's foreign ministry on Monday said it has summoned Israel's ambassador over air strikes close to Moscow's forces near the historic Syrian city of Palmyra.
Deputy foreign minister Mikhail Bogdanov told Interfax news agency that Ambassador Gary Koren was also summoned on Friday and "asked about" the strikes.
The ministry "expressed concern" about the action taking place near Russian military locations, Bogdanov said.
Russia - which is conducting its own bombing campaign in Syria in support of President Bashar al-Assad - said earlier this month that more than 180 of its troops have started demining around Palmyra's ancient monuments.
Russia and Israel have set up a "hotline" aimed at avoiding air clashes over Syria and Bogdanov said Moscow "would like this channel to work more effectively" to ensure no "misunderstanding on who is doing what."
Israeli warplanes struck several targets on Friday, prompting retaliatory Syrian missile launches, in the most serious incident between the two countries since the war began six years ago, in a strike targeting weapons bound for Lebanon's Hezbollah movement, which backs Assad in Syria.
Syria's military said it had downed an Israeli plane and hit another as they were carrying out pre-dawn strikes near Palmyra, the famed desert city it recaptured from jihadists this month.
The Israeli military denied that any planes had been hit.
On Sunday, Israeli Defense Minister Avigdor Liberman (Yisrael Beytenu) threatened to destroy the air defense system of Lebanon or Syria if either one provoked Israel, but emphasized that Israel is not interested in conflict.
Russia has deployed its own high-tech missile defense systems to Syria to protect its forces there.
On Sunday, IDF Chief of Staff Gadi Eizenkot said, "The coming war will have an address – the Lebanese government.
"Hezbollah is violating UN resolutions and is preparing for war."