The number of young children admitted to hospital suffering from severe malnutrition in Ethiopia's war-hit Tigray region has doubled this year over 2020, the UN has said, as escalating fighting threatens to further hamper the aid response.

"Some 18,600 children under the age of five in Tigray have been admitted for treatment for Severe Acute Malnutrition (SAM) from February to August this year compared to 8,900 in 2020, a 100% increase, according to UNICEF," the UN's humanitarian coordination office said in its weekly situation report for the 11-month-old conflict in northern Ethiopia.

Malnutrition among pregnant and lactating women also "continues to be very high at about 63%", the report said, while noting that only 897 aid trucks have reached the region of roughly 6 million people since mid-July -- about 14% of the estimated need.

Tigray erupted in conflict last November after Prime Minister Abiy Ahmed sent troops to topple the region's former ruling party, the Tigray People's Liberation Front (TPLF).

Two woman and a child wait to receive information about food aid distribution in Tigray

The 2019 Nobel Peace laureate said the move came in response to TPLF attacks on army camps and promised a swift victory.

But by late June, the TPLF had regrouped and retaken most of the region including the regional capital Mekele.

Since then, the region has been under a de facto humanitarian blockade, according to the UN, which estimates that hundreds of thousands face famine-like conditions.

The US has largely blamed Ethiopian government policies for the blockade, while the government has blamed TPLF incursions into neighbouring regions of Amhara and Afar.

In addition to food, the region is desperately short of medicines and medical equipment, something the UN has noted in several recent reports.

Thursday's edition said nine trucks carrying medicines remained stuck awaiting government approval in Afar, currently home to the only functioning land route into Tigray.

Polio vaccines are needed for 887,000 children and measles vaccines are needed for 790,000 children, the report said, adding that failure to administer the shots "will result in an outbreak".