Nearly 2 million refugees could flee to Turkey if the regime attacks in northwestern Syria further intensify, the U.N. said Monday.

As aid funds are dangerously low in the region, the Bashar Assad regime's indiscriminate attacks on civilians and residential buildings force tens of thousands to leave their homes. "Our fear is if this continues, and if the numbers continue soaring, and if the conflict intensifies, that we could see really hundreds of thousands, a million, two, heading towards the borders with Turkey," the U.N. Regional Humanitarian Coordinator for the Syria Crisis Panos Moumtzis said.

Idlib is the last opposition enclave in Syria. Its prewar population of 1.5 million has swelled to around 3 million after it was designated a "de-escalation zone" under the Astana agreement reached between Turkey, Russia and Iran in May 2017 to pave the way for a permanent political solution in Syria.

Tens of thousands of Syrians trapped in other parts of the country were evacuated there under various cease-fire agreements.

Following eight months of relative calm provided by the Sochi deal, reached between Ankara and Moscow, the regime has intensified attacks since April 26, under the pretext of fighting Hayat Tahrir al-Sham (HTS) militants holed up in Idlib.

The intermittent attacks and bombardments have killed, wounded and displaced thousands. Residential areas have been destroyed by indiscriminate attacks, while numerous educational facilities, health facilities and residential areas collapsed or have become unusable after being targeted by bombs.

Speaking to Reuters in Geneva, Moumtzis said: "We see an offensive that is really targeting - or with an impact on - hospitals and schools in civilian areas, in areas where there are the population and urban areas which really should not be happening according to international humanitarian law."

Aid organizations have been encouraged to share their locations with the warring parties to avoid being hit. But after repeated air strikes on hospitals, many aid workers distrust such requests, Moumtzis said.

"It's a catastrophe, what has been happening ... for the sake of humanity, there has to be an intervention," he said.

"A few months ago, we asked to make sure that this nightmare scenario will not take place. Actually, it's unfolding in front of our own eyes as we speak," he added.

Regime attacks kill 6 in Syria's de-escalation zones

Six civilians were killed and dozens were injured in recent airstrikes carried out by regime forces and Russia in northern Syria's de-escalation zones, according to the White Helmets civil defense agency.

The attacks targeted the towns of Ma'ar Shoreen, Khan Shaykhun, Al-Tamanah and Sheikh Idris in Idlib province and Hama province's towns of Ltamenah and Kafr Zayta, the agency said Monday in statement. It added that 39 civilians were injured in the attacks.