World powers are planning aid air drops to the besieged Syrian city of Deir ez-Zor, UN official Jan Egeland, head of the humanitarian task force on Syria, said Thursday.
Deir ez-Zor is encircled by Islamic State extremists.
Stephane Dujarric, a UN spokesman in New York, confirmed that the World Food Programme was considering a Russian civilian aviation contractor, which the organization had previously worked with in South Sudan, for the air drops.
Egeland was speaking after a second meeting of the International Syria Support Group in Geneva that was focused on delivering aid to all 18 besieged areas in the country.
On Wednesday, dozens of trucks carrying humanitarian aid entered five besieged areas near the capital Damascus and north-western Syria.
"We hope to be able to reach the remaining areas in the next days," Egeland said.
In the last 48 hours, 114 trucks had delivered life-saving supplies to 80,000 people, according to the Norwegian UN diplomat.
Aid was distributed in the besieged rebel-held areas of Madaya, Zabadani and Maadamiyat al-Sham near Damascus, said Linda Tom, spokeswoman for the UN Office for the Coordination of Humanitarian Affairs (OCHA) in Amman.
Supplies were also delivered to Foua and Kefraya, two government-held Shiite towns under siege for nearly 10 months by opposition Sunni rebels in the north-western province of Idlib.
In Jerusalem, Syrian rights activist Kamal al-Labwani called for a safe zone in southern Syria near the border with Israel "for civilians, to help them to rebuild their society."
He said he would try to get backing for this idea - which would initially offer some 20,000 people protection - from countries like Jordan, Turkey and Saudi Arabia.
The Syrian government said it "completely rejected" German Chancellor Angela Merkel's suggestion this week in an interview with German newspaper Stuttgarter Zeitung calling for such a no-fly zone "as helpful."
State-run SANA news agency quoted an official as saying that Merkel's comments were a violation of Syria's sovereignty and territorial integrity and "aim to protect the terrorist groups."
Intensified US-led airstrikes on Islamic State-held areas in the north-eastern province of al-Hassakeh killed 15 civilians, including three children, on Thursday alone, a monitoring group said.
In the past 48 hours, the airstrikes in al-Hassakeh have killed 48 civilians, Rami Abdel Rahman, head of the Britain-based Syrian Observatory for Human Rights, told dpa.
Meanwhile, EU leaders are expected to call on Russia and the Syrian regime to "stop at once attacking moderate opposition groups," according to a draft statement prepared for a summit taking place in Brussels on Thursday and Friday.
The attacks threaten "the prospects for peace," benefit Islamic State and fuel the refugee crisis, according to the draft, a copy of which was seen by dpa.
It also calls for the "immediate cessation of aerial bombardments in civilian areas" and urges all parties to "refrain from escalating the dire humanitarian situation" in Syria.
The statement could still be amended at the summit.