Israel is rushing to secure its northeastern border after the latest onslaught from Syrian dictator Bashar al-Assad drove 120,000 people to flee their homes.

A war monitoring group said today that most of the refugees are heading towards the border with Jordan and the Israeli-occupied Golan Heights.

A senior Israeli minister said refugees gathering at the Golan frontier must be prevented from crossing into Israel.

Syrian families' tents are seen near the Golan Heights and the Israel-Jordan border after they fled from the ongoing military operations by Bashar al-Assad regime and its supporters in Syria

A senior Israeli minister said refugees gathering at the Golan frontier (pictured) must be prevented from crossing into Israel

Jordan, already hosting some 650,000 Syrian refugees, also says its border will remain closed to more refugees. Pictured: Refugees at the Golan border

The Syrian Observatory for Human Rights said tens of thousands had gathered at Syria's border with Jordan while thousands more had fled to the Golan frontier, many of them from Nawa

Jordan, already hosting some 650,000 Syrian refugees, also says its border will remain closed to more refugees.

Syrian government forces backed by Russian air power have turned their focus to the rebel-held southwest since defeating the last remaining insurgent pockets near the cities of Damascus and Homs.

Their advances in areas east and northeast of Deraa city, and bombardment of the heavily populated rebel-held town of Nawa to its northwest, have triggered a mass flight of civilians.

The Syrian Observatory for Human Rights said tens of thousands had gathered at Syria's border with Jordan while thousands more had fled to the Golan frontier, many of them from Nawa.

Observatory Director Rami Abdulrahman said some people had also crossed into government-held areas, while others had gone to a corner of the southwest held by an ISIS-affiliated group.

'I think we must prevent the entry of refugees from Syria to Israel; in the past we have prevented such cases,' Israeli Energy Minister Yuval Steinitz, a senior minister, told Tel Aviv Radio 102FM in an interview.

Jordan says the international community must find ways to support Syrians inside Syria. 'Jordan has reached its capacity in receiving refugees,' Foreign Minister Ayman Safadi told the pan-Arab broadcaster al-Jazeera late on Thursday, affirming the government position.

The Syrian war has already displaced 6 million people inside Syria and driven 5.5 million abroad as refugees.

A lorry driving with Syrians in the back near the Golan Heights. Some 120,000 people have been displaced by recent military action

Syrian families are seen near the Golan Heights and the Israel-Jordan border after they fled from the ongoing military operations by Assad

The Syrian war has already displaced 6 million people inside Syria and driven 5.5 million abroad as refugees. Pictured: The fenced border between Israel and Syria near the Syrian village of Breqa

'Some people are sleeping under trees, others in their cars and some are setting up tents,' said Jalal al-Ahmad, an opposition activist based in southern Syria near the Golan Heights.

Israel's military said it delivered about 60 tons of humanitarian aid and medicine to thousands of displaced Syrians in the Golan Heights who flocked to the area, fleeing heavy bombardment by Syrian government forces.

Israel has been sending aid across the border for several years and has provided medical treatment to thousands of Syrians that reached the frontier with the Israel-controlled Golan Heights.

The military says it won't allow Syrians to enter Israel.

This photo released by the Syrian Civil Defense White Helmets, shows civil defense workers helping civilians who fled from Daraa after shelling by Syrian government forces, in the town of Qunaitra, near Israeli-occupied Golan Heights

Smoke rising over buildings that were hit by Syrian government forces bombardment, in Daraa, southern Syria

Civil defense workers setting up a tent for civilians who fled from Daraa after shelling by Syrian government forces, in the town of Qunaitra, near Israeli-occupied Golan Heights

A video released by Israel's military shows soldiers loading aid into trucks on the Israeli-controlled side and the cargo being then carried into vehicles by unidentified people on the Syrian side of the border.

'We left under bombardment, barrel bombs, (air strikes by) Russian and Syrian warplanes,' said Abu Khaled al-Hariri, 36, who fled from al-Harak town to the Golan frontier with his wife and five children.

'We are waiting for God to help us, for tents, blankets, mattresses, aid for our children to eat and drink.'