Head of an Iraqi NGO has said that locals in Fallujah have been prohibited from leaving the city, which is under siege from government-back militias, leading to deaths among children and the elderly from hunger.
Besides Fallujah, IS still controls Iraq's second city of Mosul, around which preparations for an offensive to retake are still at a very early stage.
"There is a serious threat of famine in Fallujah. The situation is getting worse every day for the city's residents," head of the al-Hayat Organisation, Ibtihal al-Zaidi, told The New Arab.
"Locals have repeatedly sent distress signals to the government pleading for action to be made to end their suffering. The have been several deaths of children and elderly from malnutrition and lack of medical care," Zaidi said.
Medical sources in Fallujah said earlier in January that two people had died in the city from malnutrition.
Last week, there were reports of displaced children dying of dehydration in the Amiriya refugee camp south of Fallujah because of severe shortages of infant formula.
|The recapture of Ramadi has further isolated IS-held Fallujah which lies half way on the road to Baghdad.|
Iraqi MP, Liqaa Wardi, said: "IS are using civilians as a human shield in Fallujah, where 10,000 families are besieged. IS has forbid them from leaving and security forces have failed to set up secure corridors for them to exit the city."
In a major setback for IS, the extremist group lost the city of Ramadi to US-backed local forces last month.
The recapture of Ramadi has further isolated IS-held Fallujah - which lies half way on the road to Baghdad - and undermined the viability of the group's self-proclaimed "caliphate".
The US is currently pushing Iraq to launch an assault to recapture the city of Mosul from IS with the help of "hundreds" of Western military trainers, it is still unclear when Fallujah will be recaptured.
Patrick Skinner of the US-based Soufan Group intelligence consultancy said: "The methodical taking of Ramadi, with US air cover limiting the movement and fortifications of [IS] in the urban areas, proved to be very effective. It will likely be replicated again in Fallujah."