Updated 5.45pm

An aid convoy reached rebel-held northwestern Syria Thursday, the first since a devastating earthquake that has killed thousands, an official at the Bab al-Hawa border crossing told AFP.

The 7.8-magnitude quake early Monday has killed more than 20,000 people in Turkey and war-ravaged Syria, according to officials and medics in the two countries, flattening entire neighbourhoods.

"The first UN aid convoy entered today," said Mazen Alloush, media officer at the crossing.

An AFP correspondent saw six trucks passing through the crossing from Turkey, carrying tents and hygiene products.

Alloush noted the delivery had been expected before Monday's quake, but said: "It could be considered an initial response from the United Nations, and it should be followed, as we were promised, with bigger convoys to help our people."

The International Organization for Migration (IOM) said in a statement the delivery includes blankets, mattresses, tents and "basic relief items... to cover the needs of at least 500 people".

"We are working very closely with authorities to support in any way we can and hope that aid will quickly reach those most impacted," said IOM head Antonio Vitorino.

The aid delivery mechanism from Turkey into rebel-held Syria through the Bab al-Hawa crossing is the only way UN assistance can reach civilians without passing through areas controlled by Syrian government forces.

While the crossing itself was not affected by the quake, the road leading to it was damaged, temporarily disrupting operations, a UN spokesman said on Tuesday.

'Race against time'

UN special envoy Geir Pederson said Thursday that the emergency response in Syria should "not be politicised" following "one of the most catastrophic earthquakes the region has seen in about a century".

He told reporters in Geneva that the UN had been "assured today that we would be able to get through the first assistance today".

Planes carrying aid from the United Arab Emirates, Russia, Iran and other countries have landed since Monday in Syrian government-controlled airports in Damascus, Aleppo and Latakia.

Rescuers have been searching for survivors still trapped under rubble. The White Helmets rescue group, operating in rebel-held areas of Syria, have appealed for international help in their "race against time".

The UN's resident Syria coordinator El-Mostafa Benlamlih told AFP on Wednesday that no fresh deliveries of humanitarian aid have been sent to the rebel-held northwest from within Syria in about three weeks.

He said the UN has some stocks in the area - enough to feed 100,000 people for one week.

Speaking 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."

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.