(CNN) Children and skeletal old men drinking soup made from leaves and grass. A kilo of rice costing more than $100. People said to be dying from starvation. The accounts could be of a World War II death camp, but they are not. This is Syria in 2016.

The graphic images of death and starvation coming out of the besieged Syrian town of Madaya have not been independently confirmed by aid groups or CNN. However the United Nations on Thursday said it has received "credible reports" of people dying of starvation and that the Syrian government had agreed to allow aid convoys into the besieged cities of Madaya, Foah and Kefraya.

This image of a hungry child was posted on social media by an activist in the Syrian town of Madaya. CNN cannot independently verify the image.

This image of a hungry child was posted on social media by an activist in the Syrian town of Madaya. CNN cannot independently verify the image.

Madaya: Activists post images of what they say are starving locals

Photos: Madaya: Activists post images of what they say are starving locals

One activist in the Syrian town of Madaya posted this image on social media of Abdel Karim Jawad, 60, who had died on January 2, 2016 due to starvation and lack of access to medication. CNN cannot independently verify the image or information.

One activist in the Syrian town of Madaya posted this image on social media of Abdel Karim Jawad, 60, who had died on January 2, 2016 due to starvation and lack of access to medication. CNN cannot independently verify the image or information.

Madaya: Activists post images of what they say are starving locals

Photos: Madaya: Activists post images of what they say are starving locals

One activist in the Syrian town of Madaya posted this image on social media of Suleiman Abdul-Karim Fares, 40, who had died from starvation on January 4, 2016. CNN cannot independently verify the image or information.

One activist in the Syrian town of Madaya posted this image on social media of Suleiman Abdul-Karim Fares, 40, who had died from starvation on January 4, 2016. CNN cannot independently verify the image or information.

Madaya: Activists post images of what they say are starving locals

Photos: Madaya: Activists post images of what they say are starving locals

Madaya: Activists post images of what they say are starving locals

Photos: Madaya: Activists post images of what they say are starving locals

Demonstrators in Idlib, Syria, hold banners in a protest for civilians in besieged Madaya on Tuesday, January 5.

Demonstrators in Idlib, Syria, hold banners in a protest for civilians in besieged Madaya on Tuesday, January 5.

Madaya: Activists post images of what they say are starving locals

Photos: Madaya: Activists post images of what they say are starving locals

Madaya: Activists post images of what they say are starving locals

Photos: Madaya: Activists post images of what they say are starving locals

There are conflicting reports of how many people have died. The aid group Medecins Sans Frontieres puts the number at 23 since December 1 . One activist says it could be as high as 41. The U.N. statement Thursday provided only one confirmed death, that of a 53-year-old man on Tuesday whose "family of five continues to suffer from severe malnutrition."

The U.N. World Food Programme, or WFP, was preparing to deliver humanitarian aid in the coming days, it added. A convoy, a partnership between the WFP, the International Red Cross and the Syrian Arab Red Crescent, would have enough aid to sustain 40,000 people for one month, according to spokeswoman Abeer Etefa.

Madaya, a town of 40,000 people northwest of the capital Damascus has been under siege since July, cut off by forces of both the Syrian government and Hezbollah, its Lebanese ally. Madaya is also peppered with landmines, thwarting aid efforts.

CNN Map

"People are living off nothing," Etefa told CNN's Christiane Amanpour on Thursday. "This is an area that's completely besieged and surrounded by mountains covered in snow, so the little food that gets in is through tunnels and is extremely expensive."

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Many of those posting Twitter and Facebook messages beg the world for help, saying they have no access to food, water or electricity for days at a time.

In one, a man speaks to the camera, but before long he breaks down. "What did we do? What did we do?" he cries. "My children, they're dying. Bring guns, bring angels, but God, help us," he wails.

This video, which CNN cannot independently verify, is one of dozens posted online by activists and residents in Madaya. All say they are being starved to death.

In one video , a child says he hasn't eaten for seven days and wants to eat meat. In another , a mother says her daughter has not had milk for a month. Again, neither video can be independently verified.

Children eat soup made from leaves and water, one activist, Sham Abdullah, tells CNN. He says 41 people have died so far from starvation; other activists and residents have posted images of bodies on Twitter.

In another video, an old woman stirs a pot of green boiling water. The man filming her asks in Arabic: "Hajji, what are you cooking?"

"Grass for the old man," she replies.

Food is available, resident Amjad Almaleh tells CNN, but few can afford it.

A kilo of sugar costs about $200, he says, while a similar amount of flour or rice is $120. In another tweet, there are claims milk costs $300 per liter.

"Who has that money to feed their families?" Almaleh asks. Just as others have claimed, he says parents feed stray cats and dogs to their children to keep them alive. When they can't find animals, salt and water must suffice.

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CNN contacted all groups involved in the last delivery of aid, in October 2015. All reiterate their concern for that town and dozens of others in Syria under siege.

Dibeh Fakhr, an ICRC spokeswoman in Geneva, says her colleagues who worked on the last aid drop, a joint operation with the United Nations and Syrian Arab Red Crescent, "saw hunger in the eyes of people."

"I can tell you that the situation is extremely critical. We are very concerned by all the information and images we are seeing," Fakhr says. She adds, however: "At this stage we cannot confirm reports that people are dying of starvation as we are not in Madaya."

Caught in the middle

Things have clearly worsened since October, yet the lack of independent witnesses means activists' accounts are all the world has. Landmines and a government military blockade are, residents say, responsible for the terrible situation in Madaya. It is one of many towns suffering this fate: the United Nations estimates 400,000 people live under siege as the regime and its allies fight for previously rebel-held areas.

Many observers have linked the fate of Madaya to the regime's strategy to put pressure on rebels in the north, who are blockading the towns of Kefraya and Fua. In this game of like-for-like brutality, it is the civilians who are caught in the middle.

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"Starvation and using this strategy of siege and cutting off aid and supplies is becoming an institutionalized weapon in this vicious war in Syria," Etefa said. "It's used by all the parties to this conflict. ... We need not to forget that there are others, hundreds of thousands of people, who are still in besiegement."

Five years on, this is the reality of Syria's civil war: at times the world focuses on one atrocity, but not the other.

The constant bombardment of civilian areas by the regime also gets periodic attention: for example, the strikes in mid-December (Russian, activists say) that hit children in the area of rebel-held Douma.

Yet at times this carnage becomes part of the familiar and tiring background of Syria's tragedy. The same thing happens over and over again.

With these images, Madaya has gained greater attention than many other towns besieged in this war; for now its people hope this means the world demands they receive respite.