The province of Idlib and the adjacent rural areas form the largest portion of territory still held by the besieged Syrian rebels, worn down by a succession of government victories in recent months.
President Bashar al-Assad has now set his sights on Idlib, and his forces have intensified the bombing of the densely populated province since the beginning of the month.
That has led to an estimated 30,452 people being displaced within Idlib and parts of the adjacent province of Hama between September 1 and 9, the UN humanitarian coordination agency (OCHA) said on Monday.
"We are deeply concerned about this recent escalation of violence, which has resulted in the displacement of more than 30,000 in the area, which is something we are monitoring very closely," OCHA spokesman David Swanson told AFP.
Many fled to the northern border of Syria with Turkey, and slightly less than half seek refuge in camps for displaced people and others who live with local families or rent apartments.
An AFP correspondent in Idlib has seen dozens of displaced families head towards the border in recent days to escape bombing elsewhere.
On Monday, on the main road through the province, men on motorcycles headed north with their children on foot, herding dozens of sheep.
& # 39; We escape & # 39;
Abu Jassim said he and his family were fleeing the latest bombing near the southern city of Khan Sheikhun, after being displaced several times within the province due to the war.
"They hit with four rockets, so we escaped with our flock," he said.
"We go where it's safe," said the man in his 30s.
"I have 30 sheep, I need water, hay and bran every day to feed them."
The UN has said up to 800,000 people could be displaced by an assault by the regime against Idlib and the surrounding areas.
Currently, around three million people live in the area, half of them have already been displaced by the brutal seven-year war and others that rely heavily on humanitarian aid to survive.
For weeks, the regime's troops backed by Russia and Iran have concentrated around the outskirts of Idlib, with deadly air strikes, shelling and barrel bombs that have piled up especially in recent days.
Two children were killed in barrel bomb attacks in a village in the south of Idlib, a day after 10 civilians were killed in bombings in the rebel area, the watchdog group of the Syrian Observatory for Human Rights said.
The Syrian conflict has killed more than 350,000 people and forced millions more out of their homes, but the UN has warned that a full-blown attack on Idlib could bring unprecedented suffering.
On Monday, his humanitarian chief made an urgent call.
"There must be ways of tackling this problem that will not make Idlib the next few months in the worst humanitarian catastrophe with the greatest loss of life in the 21st century," Mark Lowcock told reporters in Geneva.
The hospitals hit
He acknowledged that there were many rebels and fighters from "terrorist" groups in the province, but stressed that "there are 100 civilians, mostly women and children, for every fighter in Idlib."
Idlib is controlled mainly by Hayat Tahrir al-Sham (HTS), an alliance led by powerful jihadists who were once linked to al-Qaeda.
Its population skyrocketed when the regime won a series of victories across the country, reaching agreements that saw tens of thousands of rebels and civilians transferred by bus to Idlib.
The increasing bombing has already damaged civil infrastructure.
At least two hospitals and two centers that carry out rescue operations for the wounded were put out of service by bombings and air strikes, according to the British Observatory and the Union of Medical Assistance and Relief Organizations, which supports medical centers in Syria.
The three powerful of the conflict – the regime's allies, Russia and Iran, and Turkish rebel support – agreed at a summit last week to "stabilize" Idlib, but few details emerged about how they would do it.
The delegations of the three countries will be in Geneva on Tuesday to meet with the UN envoy in Syria, Staffan de Mistura.
Moscow wants to prevent the rebels from using armed drones against Russian fighter jets located nearby.
Meanwhile, Turkey, which already hosts three million Syrian refugees, wants to avoid an assault that would see hundreds of thousands more along its border.