The United Nations said Tuesday it would for the first time begin airlifting aid items across the border from Iraq to Syria, after receiving the go-ahead from both governments.

"Our colleagues on the Iraqi side, with the permission of the Syrian government and also the cooperation of the Iraqi government, (are preparing for the) airlifting of supplies for winter from Arbil in Iraqi Kurdistan to Qamishli and Hasakeh in north and northeast Syria," Amin Awad, who heads the UN refugee agency (UNHCR) Syria response, told reporters in Geneva.

The supplies are desperately needed in the hard-to-reach areas as the war-fatigued population braces for what is expected to be one of the harshest winters in a century, he said.

"That region of northeastern Syria has been very difficult to reach, very perilous to reach, since May," UNHCR spokesman Peter Kessler told AFP by telephone.

"UNHCR has operated an airlift from Damascus to Qamishli from July," but "this is to my knowledge the first international airlift," Kessler said.

UNHCR spokesman Adrian Edwards also told AFP that the airlift, which was set to begin on Thursday, "will be the first from Iraq to Syria".

The Syrian government had authorised the cross-border passage two weeks ago and the refugee agency had initially planned to transport aid into north and northeastern Syria by truck.

"But there was a shift in the elements that controlled that road and the border and we shifted to an airlift," Awad said. He stressed that airlifting in aid would not be sustainable in the long run.

Kessler said flights would be "carrying some 40 metric tonnes of aid, which would be... core relief items for 10,000 families, or about 50-60,000 people."

The UN's World Food Programme and children's agency UNICEF were also to send aid into Syria via air.

The UNHCR meanwhile plans to spend $195 million to help "winterise" Syria and the surrounding countries.

As part of its winterisation programme, the agency has already begun distributing things like isolation tents, plastic sheeting, warm clothing, especially for children and other vulnerable people, and cash for fuel, Awad said.

Iraq presents itself as 'neutral'

The civil war between forces loyal to Syrian President Bashar al-Assad and rebels seeking his overthrow has raged for 33 months and killed more than 125,000 people.

But Kurdish-majority areas of the country's northeast were relatively quiet until clashes broke out this year between Kurds and jihadist rebels, pushing tens of thousands of Syrian Kurds across the border into Iraq's autonomous Kurdistan region.

Iraq's federal government has publicly sought to remain neutral in the conflict, calling for an end to violence by all parties, but privately seems to lean more toward the side of Assad's regime.

According to UNHCR, Iraq's three-province autonomous Kurdistan region, from which the aid flights will depart, hosts over 200,000 registered Syrian refugees -- the vast majority of those in Iraq.

Kurdistan president Massud Barzani has been more strident than Baghdad on Syria, saying the region is prepared to strike militants anywhere, including in the neighbouring country. He earlier threatened to intervene in the conflict to protect Kurdish civilians, though officials backtracked on the remarks.

Barzani has also said that Kurdistan provided military training to Syrian Kurds so they could defend their communities, but has insisted that the Kurds should avoid being drawn into the bloody conflict.

burs-wd/rmb