The US, Britain and Canada are finalising plans to evacuate several hundred Syrian civil defence workers and their families from south-west Syria as Russian-backed government forces close in on the area, officials said.

Two officials familiar with the plans said the three countries are spearheading the evacuation that would transport members of the White Helmets group to transit camps in neighbouring countries.

From there, they will be sent to third countries, including Britain, Germany, the Netherlands and possibly Canada, according to the officials.

The officials, and a member of the White Helmets who is due to be evacuated from Quneitra province, said the operation appears to be imminent as the Syrian army continues to gain ground in its latest offensive.

The White Helmets, who have enjoyed backing from the US and other Western nations for years, are likely to be targeted by Syrian forces as they retake control of the southwest, according to the officials.

Syria evacuation
A convoy of ambulances carry Syrian citizens being evacuated from two pro-government villages in Idlib province, Syria (Sana via AP)

The officials said planning for the evacuation has been taking place for some time but accelerated after last week’s Nato summit in Brussels.

“These are hard hours and minutes,” the White Helmets volunteer in Quneitra said.

“This is the worst day of my life. I hope they rescue us before it is too late.”

The evacuation is expected to take place from Quneitra, which straddles the frontier with the Israeli-occupied Golan Heights and where the civil defence team is trapped.

It is the last sliver of land still outside government control in the region.

Since the government offensive began in June, the area along the frontier with the Golan Heights has been the safest in the south-western region, attracting hundreds of displaced people because is along the disengagement line with Israel demarcated in 1974 after a war.

The Syrian government is unlikely to fire there or carry out air strikes.

Negotiations are also ongoing to evacuate armed rebels and their families who do not want to accept the return of the rule of Bashar Assad’s government to Quneitra, which the rebels have controlled for years.

The fighters will be evacuated to the northern part of Syria, where the opposition still holds sway.

Except for that sliver of land, the southern tip of the south-western region lies along the border with Jordan and the Golan Heights and is occupied by an Islamic State-affiliated group.

The area is expected to be the target of the next government advances and the civil defence teams do not operate there.

The White Helmets are not without controversy.

They only operate in opposition-held areas, where government services are almost non-existent and aerial bombings are recurrent.

Syrian government supporters accuse them of being politically affiliated with the rebel groups.

Russia and the Syrian government have repeatedly accused them of staging chemical attacks in opposition areas, a charge that has never been proven.

They have continued to receive US support even as President Donald Trump presses ahead with his plans to withdraw all American forces from Syria as soon as Islamic State forces are routed.

In other parts of Syria, where government control has been restored, civil defence volunteers have almost always evacuated to other opposition-controlled areas.

It is not clear why this time they will be evacuated out of the country.