Witnesses said hundreds of families had begun fleeing from villages and towns in southern Idlib that have been the target of heavy strikes closer to camps near the Turkish border.
"The new policy is we're no longer pulling out by the end of the year", Jeffrey said, according to the Washington Post.
"We haven't said that the USA would use the military in response to an offensive", an administration official was quoted saying. "Every day, I need water, hay, and bran to feed them".
For weeks, regime troops backed by Russian Federation and Iran have massed around Idlib's periphery, with deadly airstrikes, shelling, and barrel bombs falling with increased intensity in recent days.
"They also include people from other parts of Syria who were transferred to Idlib, people from Homs, Aleppo, who were transferred to this province, bussed there, in evacuation deals", she said.
The Observatory said shooting broke out when Kurdish security forces at a checkpoint demanded that regime fighters step out of their patrol vehicle but they refused.
Meanwhile, the bombs keep falling.
The opposition's Civil Defence, also known as the White Helmets, said 11 people were wounded in an attack on the village of Heesh.
The local council of Morek, a town that serves as a crossing between Hama and Idlib, sent an urgent appeal, asking Turkey for a quick solution.
"There needs to be ways of dealing with this problem that don't turn the next few months in Idlib into the worst humanitarian catastrophe with the biggest loss of life in the 21st century", Mark Lowcock told reporters in Geneva.
It is estimated that between two and three million people, including around 70,000 fighters, are trapped between Syrian regime forces - backed by Russian Federation - and the Turkish border.
USA officials have said in recent days they have evidence that Syrian regime forces are preparing chemical weapons ahead of a planned assault on an opposition and rebel-held enclave in Idlib in the northwestern part of the country.
The vast majority of Idlib's population are civilians, who risk being massacred.
Now Assad, with the help of his Russian and Iranian allies, is poised for an assault on the rebels' last swath of territory, the northwest Syrian province of Idlib.
"The number is very, very little compared to three million civilians in Idlib, but there is no country in the world which can handle that number of refugees in one flow", he said.
The escalating bombardment has already damaged civilian infrastructure.
De Mistura met informally with members of the three delegations on Monday.
Observatory head Rami Abdel Rahman said the raids targeted jihadist and rebel positions, some of which were empty and others in use.
Turkey, which already hosts about 3.5 million Syrian refugees, built a four-metre wall along the frontier with Idlib in late 2016 to prevent any attacks against Turkey and stop the flow of new arrivals.