Britain said the operation was possible due to the joint diplomatic efforts, hailing the efforts of the White Helmets volunteers to save lives in opposition areas.
"We are still in danger", Abu Muhanad, another White Helmet member, told CNN.
A defense official, speaking on condition of anonymity because he wasn't authorized to discuss the event with the media, said Israel had identified two surface-to-surface SS-21 rockets launched from Syria carrying a payload of hundreds of kilograms that they believed were headed for Israeli-controlled territory.
Raed Saleh, head of the White Helmets, also known as the Syrian Civil Defense, said a number of volunteers and their families were evacuated from a unsafe, besieged area.
The plan had been to evacuate 800 White Helmets and their families, but only 422 made it. "Fantastic news that we - United Kingdom and friends - have secured evacuation of White Helmets and their families - thank you Israel and Jordan for acting so quickly on our request", tweeted British Foreign Secretary Jeremy Hunt.
The White Helmets have typically operated in opposition-held areas across Syria, places where government services are nearly non-existent, voluntarily risking their lives to save hundreds of civilians during government air strikes and bombardments.
It was unclear how many White Helmet volunteers remained in both the Daraa and Quneitra provinces after the evacuations.
Cesar says he learned of the operation a few days ago "by chance", but when he contacted White Helmets leadership, they told him it was too late to register to leave.
Pelosi to Ryan: Putin should not address Congress
When pressed by Alexander, she said she agreed with the intelligence community's assessment "full stop". The idea landed with a thud among officials back in the U.S.
Exactly when the White Helmets will arrive is unclear; the rescued Syrians are expected to remain in a United Nations refugee camp for at least three months to allow for processing.
The White Helmets have rescued thousands of civilians trapped under the rubble or caught up in fighting in opposition-held zones along various fronts of Syria's seven-year conflict.
Hundreds of volunteer rescuers have been evacuated from southwest Syria for resettlement in Britain, Canada and Germany.
Later on Monday, Israel rebuffed a new Russian offer to keep Iranian forces in Syria away from the Golan Heights ceasefire line, an Israeli official said, complicating Moscow's bid to stabilise the country as the civil war there wanes.
"Jordan is willing and encouraging the return when tension calms down because the refugees constitute a heavy burden on the kingdom in the light of the global community's inability to cover the costs", she said.
Raed al-Saleh, head of the Syrian Civil Defence, confirmed to Al Jazeera that some of its volunteers were evacuated.
Close to one million Syrians are registered with the U.N.'s refugee agency in Lebanon.
What have Israel and Jordan said?
"It seems like simple moral math to me that when the uprising fails, they should try to get their guys out alive, with their families", he told AP in an email.
Syrian state television said on Sunday an Israeli air strike had hit a military post in the city of Misyaf in Syria's Hama province but caused only material damage.