The United Nations pleaded for the facilitation of aid access to opposition-held areas in Syria's northwest, amid depleting relief stocks following the devastating earthquakes, which exacerbated the already difficult situation in the area.

Opposition-held areas near Türkiye's border — hard hit by the magnitude 7.7. and 7.6 earthquakes that struck on Monday — cannot receive aid from regime-held parts of Syria without Damascus's authorization.

"Put politics aside and let us do our humanitarian work," the U.N.'s resident Syria coordinator El-Mostafa Benlamlih said in an interview with AFP, warning: "We can't afford to wait and negotiate. By the time we negotiate, it's done, it's finished."

Monday's earthquake devastated entire sections of major cities in Türkiye and Syria, killing more than 11,700 people, injuring thousands more and leaving many more without shelter in the winter cold.

In Syria alone, at least 2,662 people have been killed, according to the government and rescuers in opposition-held areas.

Speaking to AFP from Damascus, Benlamlih said the destruction in government-held provinces "is huge."

"But we know also that the destruction in the northwest is huge and we need to get there to assess," he said.

"We still have to negotiate and we still have to get access to, for example, the northwest area, it's not easy."

No fresh deliveries have been sent to the region from within Syria in about three weeks, according to the U.N. official.

The U.N. has some stocks in the area — enough to feed 100,000 people for one week, he said.

"Once it's depleted, we need to replenish and this is my call," he said.

"We need the support of all interested parties to facilitate access, be it to the northwest of Syria or to the rest of Syria because there also, they are suffering."

On Tuesday, the U.N. said the sole border crossing used to shuttle life-saving aid from Türkiye into conflict-ravaged Syria has seen its operations disrupted.

But the U.N.'s regional humanitarian coordinator for Syria said Wednesday that he hoped aid delivery could resume as soon as the next day.

"Luckily today we are hearing that the road is opening, we do have a possibility hopefully to access the border," Muhannad Hadi said, adding that the U.N. was working with Turkish authorities.

"We are hoping that tomorrow we will be able to deliver something and cross the border," he told a news conference, noting that trucks were ready to leave if necessary.

But he cautioned that there was some uncertainty about the road on the Syrian side, citing information that was "hard to verify."

Since 2011, Syria's war has killed nearly half a million people and forced around half of the country's prewar population from their homes, with many seeking refuge in Türkiye.

Even before Monday's earthquake, the majority of the population was in need of humanitarian assistance. The latest disaster has only piled on more misery.

"This is a crisis over a crisis," Benlamlih said.

"There is not enough equipment for the search and rescue, there is not enough medical equipment, there is not enough medicine."