Fears are growing for the lives of several thousand children in northwest Burma suffering from severe malnutrition and lack of medical care but denied vital aid after a sweeping military crackdown against suspected Rohingya militants.

UN agencies were unable to maintain lifesaving services for more than 3,000 registered children, mostly from the minority Rohingya Muslim community, in two townships of northern Rakhine state after the military sealed off the area during operations in response to the killing of nine policemen in attacks on border posts on 9 October.

Following an international outcry, the military allowed the UN to resume limited aid operations in Buthidaung township in mid-December and last month in Maungdaw North.

But many of the children originally receiving aid still have not been reached while others needing help were feared also to be succumbing to severe malnourishment.

Aid workers classify the children as “indirect victims” of the conflict. They say they may be dead, missing or among the almost 70,000 who have fled across the border to Bangladesh.

“We have reports of children who died from malnutrition,” Chris Lewa, director of Arakan Project, an NGO operating for years in northern Rakhine, told The Independent. “The indirect victims of the conflict might be more than those killed,” she said. Arakan Project estimates that some 200 people were killed by the military. Other estimates range up to 1,000.

The death rate for acutely malnourished children left without support is between 30 to 50 per cent if not assisted within the first weeks, according to the World Health Organisation (WHO).

“We know from experience that as soon as there is closure then infections and diseases spread. So people who are coming [to get aid] might be completely new beneficiaries who have now become malnourished,” said one aid worker who asked not to be named.

The military said last week it had ceased operations but the conflict zone remains closed to all foreigners. Non-Burmese UN staffers have had limited access, making full counts and assessments impossible.

The 3,466 children were among a total of 13,155 listed in surveys last year as suffering from severe acute malnutrition in the two townships. An additional 60,000 children had been categorised as suffering from moderate acute malnutrition. Most belong to the stateless Rohingya minority living in utter poverty and deprived of basic rights and services for years.

“Children were receiving lifesaving and prevention treatment, and children in need who don’t receive it have a high risk of dying,” Sabah Barigou, head of the Burma nutrition unit at the World Food Programme (WFP), told The Independent.

Children belonging to a second group of 3,200 under a separate “moderate acute malnutrition” programme are now feared to have fallen into the category of severely acutely malnourished, with their lives at risk if help is not promptly resumed, senior UN sources said.

A reported increase in military checkpoints might have deterred families from travelling to obtain aid.

“The reports we have been receiving indicate that some people are not leaving their villages out of fear, even when services are available,” said Mark Cutts, head of the UN Office for the Coordination of Humanitarian Affairs. “The suspension of critical lifesaving humanitarian operations for over two months clearly had consequences, particularly for children who were already severely malnourished.”

But without proper access it was difficult for the UN to quantify, he added.

“Humanitarian action is not just about delivering food and other relief supplies. It's about ensuring that people are safe and that they have adequate access to health care and other essential services,” said Mr Cutts.

Procedures to check whether some children had reached refugee camps in the port of Cox’s Bazar in Bangladesh are moving slowly as most lack any documentation.

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The crackdown is the worst since 2012 when communal violence between the Muslim minority and the military backed Buddhist majority resulted in more than 200 deaths and the forced detention of over 140,000 people, mostly Rohingya, in camps.

According to Unicef, Burma is one of 36 countries with the highest burden of chronic malnutrition. A third of children under five are identified as “stunted”.

Malnutrition has been exacerbated by decades of low-level conflict in ethnically mixed border areas, not just Rakhine where poverty is also widespread among the majority Buddhist population. However malnutrition rates are higher among the Rohingya, with one in five children acutely malnourished.

In the conflict areas of Maungdaw and Buthidaung acute malnutrition was above the WHO emergency threshold even before the military crackdown began in October. The World Food Programme had been delivering therapeutic food fortified with supplements, and medical care. Mothers were also taught how to nourish children unable to eat or drink due to illnesses.

Burma’s civilian government led by Aung San Suu Kyi, who has little or no control over the military in their nearly year-old power-sharing arrangement, is starting to react to mounting international pressure. A damning report by the UN human rights office prompted the government to set up a commission to investigate alleged human rights abuses despite its initial denials of reports of killings, rape and mass arrests.