"We can not see a military solution, it can not take place", he said.
The villages of Fuaa and Kafraya represent a tiny pocket of regime-held territory in Syria's northwest Idlib province, which is otherwise nearly entirely controlled by various jihadist and hardline rebels.
Representatives of civil defense Idlib (White helmets - ed.) confirmed the attack on the building of children's hospital in Tetanus, and said that killed five people, including three children. "Our worry is that with the Idlib situation we may have not (yet) seen the worst in Syria".
He said the world must "make sure that we don't see a similar scenario as we saw in Eastern Ghouta", which was recaptured in April by the Syrian government after a blistering two-month offensive.
OCHA is on "high alert" for possible further displacement among the estimated two and a half million people in Idlib, adding "There is no place left to go" within Syria.
In this January 11, 2013 file citizen journalism image, provided by Edlib News Network, ENN, which has been authenticated based on its contents and other AP reporting, rebels from al-Qaida-affiliated Jabhat al-Nusra, also known as the Nusra Front, wave their brigade flag, as they step on the top of a Syrian air force helicopter at Taftanaz air base that was captured by the rebels in Idlib province, northern Syria.
Following the Eastern Ghouta offensive, and the previous offensive to retake Syria's second city Aleppo, rebels and civilians were forcibly evacuated to Idlib.
"Really, this is the last location".
At the same time, the mishmash of armed groups in the province are increasingly fighting amongst themselves.
Two more civilians, including a child, were killed in other raids nearby.
"This is the fiercest attack in around three years", said Abdel Rahman.
An aid convoy reached Douma in the enclave of eastern Ghouta outside Damascus on Sunday, but the government did not allow United Nations aid workers to accompany it, he said, saying that direct access was vital.
Elsewhere, access is easier and the United Nations is now providing aid to some 5.5 million people across the country each month. Under the Astana agreement, Turkey is to gradually establish 12 observation points from Idlib's north to south to monitor and sustain the current ceasefire agreement for the de-escalation zones, deliver humanitarian aid and ensure the secure return of displaced people. "Our warehouses are empty".