WASHINGTON (AP) — U.S. officials say the United States is finalizing plans to evacuate several hundred Syrian civil defense workers and their families from southwest Syria as Russian-backed government forces close in on the area.

Two officials familiar with the plans said Thursday that the U.S., Britain and Canada are spearheading the evacuation that would transport members of the White Helmets group to transit camps in neighboring countries. From there, they will be sent to third countries, including Britain, Germany, the Netherlands and possibly Canada, according to the officials who spoke on condition of anonymity because they were not authorized to publicly discuss the matter.

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 U.S. 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.

The officials said planning for the evacuation has been underway 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, speaking on condition of anonymity for fear for his life. “This is the worst day of my life. I hope they rescue us before it is too late.”