A second batch of sick Syrian civilians, most of them children, left the besieged rebel enclave of Eastern Ghouta, aid officials said on Wednesday.
However, hundreds of critical patients remained trapped.
Four evacuations took place on Tuesday and another group of 12 made it out late on Wednesday, but a top humanitarian envoy questioned a deal under which medical emergencies are used as bargaining chips.
A total of 29 emergency medical cases are expected to be evacuated under a deal with the government that saw rebels release 26 individuals, including workers detained during fierce clashes with the army in March.
The numbers are still a far cry from the nearly 500 patients in the Damascus suburb the UN said weeks ago would die if they did not urgently receive better treatment.
"Yesterday we evacuated 12 patients together with their family members, the majority of them are children," International Committee of the Red Cross spokeswoman Ingy Sedky said.
At the Syrian Red Crescent headquarters in Douma, a correspondent saw the latest group of evacuees waiting for ambulances to pick them up.