"If the opposition does not participate there will be no Geneva conference," Brahimi told reporters at a press conference to wrap up his days-long trip to the Syrian capital, Damascus.

His remarks coincided with a UN food agency warning that malnutrition is worsening among children trapped in besieged areas of Syria.

"The participation of the opposition is essential, necessary and important," Brahimi said, adding that the proposed "Geneva II" conference was intended "to help the Syrians and resolve their problems."

Brahimi also said he hoped that the conference would be held "in the coming weeks, not next year or after that."

The intended Geneva meeting, aimed at ending Syria's two-and-a-half-year civil conflict, has been repeatedly delayed by disputes between world powers, divisions among Syria' opposition and the inflexibility of both sides.

Brahimi, who is on a Mideast tour in a bid to garner regional support for the peace conference, said Syrian President Bashar al-Assad had agreed to the participation of his government in Geneva.

"The opposition, whether the National Coalition or others, are trying to find a way to be represented," he added.

Opposition rejects Assad attendance

Many figures in Syria's fractured opposition want international guarantees either that Assad will step down or not be part of a negotiated solution as a pre-condition for their taking part in Geneva.

The opposition coalition is to meet on November 9 to decide whether to attend.

'Many' civilians trapped, children malnourished

In Geneva on Friday, UN World Food Program (WFP) spokeswoman Elisabeth Byrs said "many Syrians" remained trapped in conflict areas.

"We are monitoring worrying reports emerging of malnutrition among children in besieged areas," Byrs said.

Teams comprising the WFP and Syria's Red Crescent had been unable to reach 38 locations since mid-2012. Although assistance reached 3.3 million in October, the WFP was stilll 700,000 short of its target, she said.

Among them is the town of Moadamiyet al-Sham, near Damascus.

We've tried unsuccessfully nine times to reach Moadamiyet since last year, she said.

In a rare moment on Tuesday, coordination between rebels and the government enabled 1,800 civilians to free the besieged town. Thousands remain trapped with little food, water or medicine.

50 checkpoints, says IRC

International Red Cross director of operations Pierre Kraehenbuehl said in Geneva that aid deliveries to Aleppo in northern Syria had to pass through "between 50 and 60 checkpoints."

Because of "very strong fragmentation" among opposition groups," aid delivery workers had to negotiate en route with a "multiplicity" of groups, Kraehenbuehl said.

More than 100,000 people have died in the Syrian conflict and millions have been driven from their homes since a government crackdown on initially peaceful protests in March 2011.

tj/ipj (AP, Reuters, AFP)