CANBERRA, Australia — Aid agencies have been overwhelmed by demand for food in Syria, with thousands surviving without a regular supply of nourishment for more than a year because of civil war in the Middle Eastern country, a United Nations official said.

UN World Food Program chief executive Ertharin Cousin was in the Australian capital Canberra on Monday for talks with the new Australian government about the financial needs of the world’s largest humanitarian organization which she leads.

The Rome-based American said gaining access to besieged areas was the biggest challenge in feeding the 6.5 million people in need within Syria’s borders. Another two million Syrians who had fled the conflict relied on food aid in neighboring Lebanon, Iraq, Jordan, Turkey and Egypt.

“The level of need is much higher than what we’re actually achieving in Syria,” Cousin said.

She said 45,000 families in the northeast province of Hassaka were among the Syrians who had survived without regular food deliveries for more than a year.

WFP airlifted food from Iraq to 6,000 families in Hassaka in December last year at a transport cost of $800,000. More airlifts were planned for next week.

“Despite the cost, we know that that’s the only way right now that we can reach those families in Hassaka,” Cousin said.

“What that means is that we can provide less food to fewer people when we use resources that should be going to feed people to pay for airplanes,” she added.

Cousin said she was aware of anecdotal reports of Syrians starving to death in areas of the country that aid agencies could not access. But WFP had no evidence to corroborate such reports of starvation.

“But when you know that people have no resources, no access to … food, and you’re not reaching them, those anecdotes become easier to believe,” she said.

Syria was forecast to cost the WFP more than $1 billion this year — a quarter of the organization’s global budget, Cousin said.

WFP had set a goal of feeding 4.25 million people in Syria, but was currently reaching fewer than 4 million, she said.

Other aid agencies including International Committee of the Red Cross were attempting to feed others among the 6.5 million Syrians in need, she said.

Syria’s conflict, which began in March 2011 as a street uprising against President Bashar Assad’s family rule, has killed more than 136,000 people, according to the latest count by the Britain-based Observatory, which tracks the missing and killed through a network of informants on the ground.

The war has also forcibly displaced one-third of Syria’s prewar population of 23 million.

Copyright 2014 The Associated Press.