Dozens of children, elderly people and others displaced by the Syrian conflict have starved to death in a besieged camp in Damascus, according to reports.

The sprawling Yarmouk camp, in the southern suburbs of the city, is home to tens of thousands of Palestinian refugees and displaced Syrians who have been trapped under a year-long blockade.

"There are no more people in Yarmouk, only skeletons with yellow skin," said Umm Hassan, a 27-year-old resident and mother of two toddlers. "Children are crying from hunger. The hospital has no medicine. People are just dying." Her three-year-old daughter and two-year-old son were rapidly losing weight from lack of food, she added.

Since October, 46 people have died of starvation, illnesses exacerbated by hunger or because they could not obtain medical aid, residents said. Similar casualty figures have been reported by the British-based Syrian Observatory for Human Rights.

The dead include Isra al-Masri, an emaciated toddler who died on Saturday. Other deaths underline the extent of desperation among residents: teenager Mazen al-Asali hanged himself in late December after returning home without food to feed his starving mother; an elderly man was beaten to death by thieves who ransacked his home, looking for food and money.

The UN confirmed 15 deaths, but a spokesman, Chris Gunness, said it was impossible to know the real toll because of restricted access. "There is profound civilian suffering in Yarmouk, with widespread malnutrition and the absence of medical care," he said. "Children are suffering from diseases linked to severe malnutrition."

The UN humanitarian chief, Lady Amos, warned last month an estimated 250,000 people in besieged communities in Syria were beyond the reach of aid. Key routes are increasingly cut off by the fighting, and kidnappings of aid workers have increased.

The Yarmouk camp and other blockaded areas pose a stark challenge for Syria's government and opposition, who agreed to consider opening humanitarian access in the runup to the Geneva II peace conference in Switzerland next week, which would bring the opposing sides together for the first time.

Speaking this week during a two-day series of meetings in Paris, Russia's foreign minister, Sergey Lavrov, and the US secretary of state, John Kerry, said they would also press for a ceasefire and prisoner exchange between the warring groups.