Every time Mohamed Jimon climbs into the cab of his tractor-trailer, he knows danger is just down the road.

Whether it's holes blown in highways by airstrikes or the threat of ending up at a hostile checkpoint, Jimon's job as a truck driver delivering emergency aid to communities in Syria is risky but vital, he says.

"It's important for the hungry people of Syria," Jimon said while waiting for his rig to be loaded in southern Turkey. "So that they have something to eat, so they can survive."

Jimon is a truck driver supporting the relief effort organized by the United Nations to get food, medicine and other supplies to Syrians who lack most of the basics needed to survive.

The United Nations Office for the Co-ordination of Humanitarian Affairs (OCHA) says it's doubled the number of trucks over the past year that are providing assistance to slightly more than two million Syrians.

Mohamed Jimon securing load

Syrian truck driver Mohamed Jimon secures a load of humanitarian aid he will deliver to parts of Aleppo province. (Derek Stoffel/CBC)

This effort is separate from the convoys that are now rolling into seven areas in Syria that have been been besieged by Syrian government or rebel forces.

On Tuesday, the UN's envoy to Syria, Staffan de Mistura, negotiated an agreement with the Syrian regime of President Bashar al-Assad to allow emergency aid to flow to the cut-off communities. The first Syrian Red Crescent trucks arrived in some towns Wednesday.

"It is the duty of the government of Syria to want to reach every Syrian person wherever they are with humanitarian aid, particularly now after [such a] long time," said de Mistura.

Fingers crossed

World powers continue to press for a "cessation of hostilities" in Syria on Friday, even though the Syrian regime and some rebel groups have indicated they will not halt the fighting.

But aid agency officials still have their fingers crossed.

Mohamed Jimon in truck

Syrian truck driver Mohamed Jimon sits inside the cab of his truck, which was damaged Monday in what he says was the shock felt after an airstrike in Aleppo province. (Derek Stoffel/CBC)

"It would mean that aid could get into areas that have been besieged, where they've been encircled by one party or another," said Barbara Shenstone, who runs the UN OCHA office in Gaziantep, Turkey.

"Everybody would welcome a cessation in fighting."

Relief organizations have struggled to offer assistance to those affected by Syria's long war, which the UN says has left at least 250,000 people dead.

But aid agencies, often relying on Syrian staff, have continued to deliver food, medicine and other supplies, often at great risk to the personal safety of the local employees.

Health-care workers in Syria have also paid a high price for trying to heal those injured in the conflict.

According to a September 2015 report by the World Health Organization, 654 Syrian medical workers have been killed since the start of the war five years ago.

Trauma services hindered

Dr. Khaled Almilaji has lost colleagues and seen bombed-out hospitals in his native Syria.

Almilaji runs the Turkey office of the Canadian International Medical Relief Organization, which helps train health-care workers and provides emergency treatment in war zones.

"Hospitals which are there to receive patients are now directly targeted in attacks," he told CBC News.

Humanitarian aid

Humanitarian aid consisting of soap and other hygiene products was loaded onto a truck bound for Syria at a United Nations staging areas in Kilis, Turkey. (Derek Stoffel/CBC)

Since Syrian government forces began their assault on Aleppo province, in northern Syria, at the beginning of the month, trauma services have been severely hindered, Almilaji said.

Before the offensive, Syrians injured in the war or those requiring serious medical treatment for other reasons often were taken by ambulance to Turkey. But now, most of the roads leading north have been cut off or are too dangerous.

"People in those areas are waiting and there is nothing to help them because [they are in] besieged areas, and actually most of them are now dying," Almilaji said.

Despite the risks, however, doctors and nurses continue to treat the wounded, even after a number of attacks earlier this week on four medical facilities in northern Syria that left nearly 50 people dead, including health-care workers.

And those UN convoys continue to roll across the Turkish-Syrian border, with determined drivers behind the wheels.

"It's difficult. Sometimes I think death would be easier," said Jimon. "But we have to continue. It's too important. We cannot stop."