BEIRUT/JERUSALEM (Reuters) - The Israeli air force struck a position on Friday on the Syrian side of the Golan Heights frontier, sources on both sides said.

An Israeli air strike targeted a hill in Khan Arnabeh village in Quneitra province without causing casualties, a commander in the pro-Damascus regional alliance told Reuters.

Israel’s military said it struck a Syrian army post that had shelled a buffer zone on the Golan frontier during fighting with rebels in southern Syria.

With the help of Russian air power, Syrian government forces have swept into insurgent territory in the south over the past two weeks. The offensive has so far focused on Deraa province near Jordan’s border, not Quneitra further west near the Israeli-occupied Golan Heights.

In its statement on Friday, the Israeli military said that, while not involved in Syria’s war, it would “continue to implement the 1974 Separation of Forces Agreement that includes maintaining the buffer zone”.

The U.N.-monitored 1974 armistice bars or limits military build-ups by either side around the Golan. An Israeli cabinet minister said on Thursday that Israel could fire upon any Syrian forces it deems to be violating the truce deal.

Israel, which annexed the Golan after seizing much of it from Syria in the 1967 Middle East war, has beefed up its tank and artillery forces on the plateau.

Israel has been watching warily as Syrian President Bashar al-Assad’s military and its allies advance near the Golan. During Syria’s seven-year war, it has conducted scores of air strikes on what it describes as Iranian or Tehran-backed targets.

Prime Minister Benjamin Netanyahu, who will meet Russian President Vladimir Putin in Moscow next week, has been pressing Moscow to keep Assad’s Iranian allies away from the frontier.

Lebanon’s Iran-backed Hezbollah is helping to lead the offensive in south Syria but keeping a low profile, pro-Damascus sources have told Reuters, in defiance of Israeli demands.