ALEPPO, Syria: Residents of Aleppo have suffered through months of brutal urban warfare and now face a humanitarian crisis with a lack of food and fuel as the Syrian winter sets in.

From throngs outside bakeries hoping for increasingly expensive bread to boys tying ropes around trees to pull them down and chop them up for firewood, the city that was once Syria's commercial hub is now barely surviving amid appeals for more international support.

"Oil and food is very expensive," said one fruit vendor, who did not give his name. "The problem is not for fruit -- the problem is bread and fuel."

Next to him, another vendor pointed to a park across the street and said that months ago, it was filled with trees that have since been chopped down to be used for fuel.

Battles between forces loyal to embattled President Bashar al-Assad and rebels in the northern city have raged since July, and now many rebel-held areas of Aleppo have been cut off from old supply lines for flour and fuel.

Frequent shelling, gunfire and other attacks also dissuade many residents from moving around, especially in areas close to the frontline.

As a result, Aleppo -- like much of Syria -- is struggling with a bread shortage, but also suffers from shortfalls of fuel for electricity and heating, and key medical supplies.

The few who can afford them use private generators, but the vast majority in rebel-held areas of Aleppo have no electricity, and bakeries cannot satisfy the demand for bread, with prices shooting up.

Traditional pieces of round flat bread, typically sold in packs of eight, now cost more than three times as much at bakeries that receive subsidised flour as before a rebel offensive in Aleppo in the summer.

At bakeries that procure flour privately, prices are higher still, far beyond the reach of most in the city.

Prices for gasoline, heating fuel and firewood have also skyrocketed.

The situation has become so bad that the United Nations on Wednesday appealed for $1.5 billion to help Syrians fleeing the fighting, describing the conflict as "increasingly brutal and indiscriminate."

According to one Czech aid group, residents in Aleppo sometimes begin queuing overnight at subsidised bakeries, where hundreds often line up in the hope of securing some bread.

"They have no access to bread, they have no access to healthcare," said Michal Przedlacki, Syria mission head of the NGO, People in Need. "Winter will be brutal, not only because of the fighting, but also because of the conditions.

"We have no idea how they will get through the winter."

He added: "There is almost no international aid present on the ground, especially deeper inside Syria."

People in Need has for the past several weeks been distributing basic food supplies such as sugar and canned meat to desperate families in Aleppo, but lacks funding to expand its efforts.

Exile groups are also looking to pitch in, with the Transitional Revolutionary Council of Aleppo, which has received $1 million from the opposition National Coalition, planning to truck in diesel to help power bakeries and mills.

"The mills can't work because there is no electricity and no diesel," said Hakeem al-Halbooni, part of the council's three-member presidential council.

"The biggest issue now is diesel, in order to generate power for the mills and the bakeries," said Halbooni, speaking in the lobby of a hotel in the Turkish city of Gaziantep where he was holding meetings with other council members.

Halbooni did not specify how much fuel would be shipped in to Syria from Turkey, or at what cost, but said the council was hoping to receive more funds from the coalition and the international community to increase supplies.

"This has to be conveyed to the Western world, that when you let Bashar al-Assad bomb them (Aleppo residents) day and night without acting, people are frustrated with Western governments," he said.