Israel said it fired artillery shells Tuesday at Syrian-held positions on the Golan Heights after at least two rockets struck the Israeli-controlled side of the plateau.
The initial fire did not cause any injuries in Israeli-held territory, a military spokeswoman said.
The Israeli military also said it evacuated the Mount Hermon ski site on the Israeli-controlled side of the Golan.
The Britain-based Syrian Observatory for Human Rights said the Israeli shells hit areas where the Syrian Army’s 90th Brigade is positioned.
Activists in the area said at least 15 artillery shells fell on the area.
The Israeli military has been on high alert along the border with Lebanon and Syria since an alleged January 18 airstrike on the Syrian-controlled side of the Golan Heights, which left six militants of the Iranian-backed Lebanese radical Shiite Hezbollah movement and an Iranian general dead.
Israel has neither confirmed nor denied that it carried out the airstrike, which exposed Hezbollah’s and Iran’s presence on the Syrian side of the strategic plateau.
Most of the Syrian side of the Golan has been captured by rebel forces with the al-Qaeda-affiliated al-Nusra Front playing a prominent role.
The rebels have pressed on eastwards to government positions in Daraa province in one of their few successful offensives of the past two years.
Syria denounced the January airstrike as proof that Israel was supporting the rebels, whom it denounces as terrorists.
The dead in that strike included Jihad Mughniyeh, the son of Hezbollah military commander Imad Mughniyeh, who was himself slain in a 2008 car bombing in Damascus, which the group also blamed on Israel.
Iran’s Fars News Agency reported that Mohammed Ali Allahdadi, a senior officer in the elite Revolutionary Guard, was also among those killed.
Iranian and Hezbollah officials have vowed retaliation.
Israel captured the western part of the Golan from Syria in the 1967 Six-Day War.