Dozens of Syrians approached the Israeli frontier on the Golan Heights on Tuesday in an apparent attempt to seek help or sanctuary from a Russian-backed Syrian army offensive, before turning back after a warning from Israeli forces.

Tens of thousands of Syrians have arrived near the frontier with the Israeli-occupied Golan Heights in the past month, fleeing a rapidly advancing offensive which has defeated rebels across a swathe of territory near Jordan and Israel.

"Go back before something bad happens. If you want us to be able to help you, go back," an Israeli army officer on the Israeli side of a frontier fence told the crowd in Arabic through a megaphone. "Get a move on."

The offensive has triggered the single biggest displacement of the war, with several hundred thousand people uprooted. Both Israel and Jordan have said they will not allow Syrians to cross into their territory.

Israel, which seized the Golan in the 1967 Middle East War, has given humanitarian aid to refugees in encampments close to a 1974 Israeli-Syrian disengagement line. Many of the displaced are sheltering within the disengagement zone that is monitored by a UN force.